How  WE  Live 

OR 

THE  HUMAN  BODY 

AND  HOW  TO  TAKE  CARE  OF  IT 


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HOW  WE  LIVE 


OR, 


THE  HUMAN  BODY,  AND  HOW  TO 
TAKE  CARE  OF  IT. 


AN  ELEMENTARY  COURSE  IN  ANATOMY, 
PHYSIOLOGY,  AND  HYGIENE. 


BY 

JAMES   JOHONNOT 

AND 

EUGENE    BOUTON,    Ph.D. 


REVISED  AND  APPROVED  BY 

HENRY    D.    DIDAMA,    M.D., 

WIOFESSOR    OF     THE     PRINCIPLES     AND      PRACTICE     OF     MEDICINE     IN     THE     COLLEGE 

OF   MEDICINE,    SYRACUSE   UNIVERSITY;     EX-PRESIDENT   OF   THE    MEDICAL 

SOCIETY    OF    THE    STATE    OF    NEW    YORK,     AND    OF    THE 

NEW    VOKK    STATE    MEDICAL    ASSOCIATION. 


NEW  YORK  •:•  CINCINNATI  •:•  CHICAGO 

AMERICAN     BOOK     COMPANY. 

FROM   THE    PRESS   OF 

D,  APPLETON  &  COMPANY. 


JimocAa'ioa  iiBH,'' 


Copyright,  1884,  1885. 
Bv  D.  APPLETON  AND  COMPANY. 


WHY  AND  HOW. 


For  a  long  time  the  conviction  has  been  grow- 
ing that  there  is  a  radical  defect  in  an  elementary 
course  of  study  which  admits  technical  grammar, 
but  excludes  physiology,  and  which  makes  more  of 
the  classifications  of  expression  than  of  the  thought 
to  be  expressed.  The  urgent  need  has  long  been 
felt  of  giving  more  attention  to  subjects  pertaining 
to  life,  those  that  may  be  a  guide  to  thrift,  health, 
and  happiness. 

Legislative  Action. 

These  convictions  seem  to  have  been  shared  by 
the  law-makers  of  New  York  and  several  other 
States.  The  recent  enactments  making  physiology 
a  part  of  the  course  of  instruction  in  the  public 
schools  are  evidences  of  this  conviction  ;  and  from 
every  point  of  view  the  measures  appear  wise  and 
beneficent. 

If  wisely  carried  out,  this  law  must  be  produc- 
tive of  great  good.  fThe  attention  of  pupils  will  be 
directed  to  the  laws  which  govern  their  own  being. 
The  truths  set  forth  will  find  lodgment  in  the  brain, 
and  in  time  they  will  find  expression  in  daily  prac- 
tice. As  a  result,  we  may  look  for  improvements 
in  food,  in  dress,  in  ventilation,  in  habits,  in  hours 

M750313 


6  IVHV  AND  HOW. 

of  work  and  recreation,  and  in  everything  that  per- 
tains  to  living. 

Plan  of  the  Book. 

The  manifest  importance  of  the  subject  is  the 
*'  why  "  of  the  book.  The  "■  how  "  remains  to  be 
considered. 

The  book  is  elementary,  not  a  scientific  treatise 
for  advanced  students.  Beginning  with  obvious 
relations,  its  method  is  inductive,  each  new  topic 
growing  out  of  the  one  that  precedes  it.  It  aims  to 
present  the  laws  of  life  in  such  a  practical  and  rea- 
sonable way  that  they  will  become  a  guide  to  living. 

In  the  treatment  of  each  topic,  function  is  con- 
sidered before  structure.  The  first  step  is  to  show 
that,  for  purposes  of  life  and  growth,  there  is  a  need. 
Then,  in  answer  to  the  query  as  to  what  is  done  to 
satisfy  the  need,  a  full  description  is  given  of  the 
organs  used  and  the  methods  employed.  This  prop- 
erly subordinates  structure  to  use,  and  shows  the 
true  relations  of  all  the  agencies  of  life. 

The  limitations  set  by  the  term  ''elementary" 
have  forbidden  minute  details,  abstruse  discussions, 
and  ultimate  analyses.  All  these  are  left  for  the 
"  High-School  Physiology." 

Hygiejiic  Lazvs. 
An  endeavor  has  been  made  to  present  the  rela- 
tions of  part  to  function  in  such  a  way  that  the 
hygienic  law  applicable  to  the  case  follows  as  a 
matter  of  course,  and  scarcely  needs  to  be  stated, 
A  law  derived  in  this  way  compels  assent  and  com- 


IVHV  AND  HOW,  7 

mands  obedience ;  while  one  learned  from  the  book 
is  likely  to  remain  in  the  mind  as  a  mere  formula. 

Incentives  to  Study. 

At  the  close  of  each  chapter  a  list  of  questions 
is  appended,  not  on  the  text,  but  rather  on  subjects 
which  the  text  suggests.  The  answers  to  these 
questions  wall  test  the  pupil's  powers  of  inference, 
and  will  incite  to  careful  observation  and  study  in 
various  directions.  When  the  questions  are  not 
matters  of  mere  inference,  one  at  a  time  should  be 
given  out  at  the  close  of  each  recitation,  so  as  to 
allow  ample  time  for  mquiry  and  study.  The  good 
which  will  come  from  a  judicious  use  of  these  topics 
may  be  lost  by  a  rigid  demand  for  a  specific  answer 
in  a  specified  time. 

Alcohol  and  Narcotics. 

The  provision  in  the  new  laws  in  regard  to  al- 
cohol and  narcotics  seems  to  be  another  wise  and 
timely  measure.  It  assumes  that  bad  habits  are 
largely  due  to  ignorance.  It  would  diminish  the 
evils  by  removing  the  cause.  It  submits  the  solu- 
tion of  a  great  social  problem  to  science.  It  es- 
pouses no  theories,  but  demands  the  exact  truth. 
It  calls  upon  the  teacher  to  furnish  the  weapons 
that  shall  conquer  prejudice,  and  arm  the  inexperi- 
enced against  temptation. 

In  this  work,  alcohol  and  narcotics,  in  their  rela- 
tions to  life,  are  duly  treated.  Wherever  they  are 
found   in  the  body,  their  effects  upon  organ  and 


8  •      lV//y  AND  HOW. 

function  are  fully  described.  These  effects,  on  the 
whole,  are  seen  to  be  so  pernicious  that  a  knowl- 
edge of  them  would  seem  to  be  an  almost  sufficient 
safeguard  against  evil  example,  which  is  continually 
inciting  to  evil  habits. 

The  error  of  over-statement  has,  however,  been 
carefully  avoided.  Assertion  without  reason  weak- 
ens a  cause.  The  facts  are  sufficient.  A  serious 
mistake  is  made  when  the  suspicion  is  aroused  that 
an  effort  is  made  to  establish  a  case,  rather  than  to 
ascertain  and  state  the  truth. 

Practical  Application. 

This  and  all  kindred  works  will  be  of  little  use  if 
thought  stops  with  the  text.  What  is  said  is  valua- 
ble only  as  it  "■  wakes  up  mind,"  and  leads  to  further 
study,  and  to  the  observance  of  hygienic  laws  in  daily 
practices.  The  teacher  who  allows  his  pupils  to  sit 
in  draughts,  and  pays  no  heed  to  ventilation  and  the 
arrangement  of  light,  and  who  is  careless  in  regard 
to  his  own  diet,  dress,  and  hours,  of  sleep,  will  teach 
physiology  to  little  purpose. 

The  pupils  should  be  made  to  see,  to  study,  and  to 
experiment.  The  word  should  lead  to  work.  Prin- 
ciples should  direct  practices.  The  understanding 
of  conditions  must  precede  conscious  obedience  to 
law,  but  obedience  is  the  desired  end.  Full  mental 
conception  of  the  subject  in  its  relations  will,  in  time, 
yield  fruit  in  the  direction  of  more  healthful  bodies, 
more  vigorous  minds,  and  lives  made  richer  by  the 
accomplishment  of  good  deeds. 


WHAT  AND  WHERE. 


CHAPTER  J. 

PAGE 

The  Body  and  its  Parts 13 

Why  we  should  Study  our  Bodies  :  Some  Things 
easily  seen — Others  require  Study — Natural  to  avoid  injur- 
ing Outward  Parts  of  the  Body — Study  needed  to  know  how 
to  take  care  of  Organs  within  the  Body — Why  we  should  look 
well  and  keep  healthy.  About  Parts  of  the  Body  : 
The  Arms — The  Legs — The  LimBs  and  Joints — Parts  of  the 
Body  in  Pairs — The  Bodies  of  other  Animals — Uses  of  the 
Parts  of  the  Body.    Something  to  Find  Out. 

CHAPTER   n. 

Eating,  and  what  Comes  of  It 21 

Why  we  Eat  :  The  Body  always  wearing  out — We  eat 
that  we  may  live.  What  we  Eat  :  Kinds  of  Food — ^Value 
of  Different  Kinds — Special  Foods — Mixed  Foods.  How  we 
Eat  :  Mastication— The  Teeth— Care  of  the  Teeth— How  to 
keep  the  Teeth  clean.  How  we  Swallow  :  How  Saliva 
flows — Amount  of  Saliva — How  Saliva  is  wasted — Tobacco 
— The  Esophagus.  Hygiene  of  Mastication.  Some- 
thing to  Find  Out. 

CHAPTER   HI. 
How  Digestion  Goes  On 35 

The  Stomach  :  Structure — Muscular  Action — Gastric 
Juice — Changes  in  the  Stomach — Chyme — The  Absorbents — 


10  WHAT  AND    WHERE. 

PACK 

Drink — Alcohol  in  the  Stomach — Absorbing  Power — The 
Alcohol  Habit.  The  Intestines  :  Structure — Intestinal 
Juices — The  Duodenum — The  Pancreas — Office  of  the  Pan- 
creatic Juice — The  Liver — Bile — Office  of  the  Bile — Chyle — 
Alcohol  in  the  Liver — Absorption — The  Portal  System — The 
Lacteals — The  Thoracic  Duct — Summary  of  Changes.  Hy- 
giene OF  Digestion.    Something  to  Find  Out. 

CHAPTER   IV. 
How  THE  Blood  gets  Purified 46 

The  Heart:  Its  Position— The  Plan  of  the  Heart- 
Auricles  and  Ventricles — Pulmonary  Action.  The  Lungs  : 
Structure  of  the  Lungs — Bronchial  Tubes — The  Trachea — 
The  Larynx — The  Pleura — How  the  Chest  varies — Forces  in 
Breathing — Inspiration — Expiration — Action  in  the  Lungs — 
Results  of  Breathing — Return  of  the  Blood — Alcohol  in  the 
Lungs — An  Unnecessary  Burden — Tobacco  in  the  Lungs — 
Produces  Stupor — The  Need  of  Pure  Air.  Hygiene  of 
Respiration.    Something  to  Find  Out. 

CHAPTER  V. 
How  the  Blood  Nurtures  the  Body  ..       .       .       .58 

Waste  and  Repair — The  Arteries — The  Capillaries — The 
Veins — Action  in  the  Heart — Action  in  the  Arteries — Action 
in  the  Capillaries— Action  in  the  Veins — Alcohol  in  the  Blood 
— Does  not  become  a  Part  of  the  Blood — Hinders  the  Effect 
of  Oxygen — Injures  the  Walls  of  the  Heart — Enlarges  Mi- 
nute Divisions  of  the  Arteries.  Hygiene  of  Circulation. 
Something  to  Find  Out. 

CHAPTER   VI. 

How  the  Body  is  Able  to  Move 66 

Motion  necessary  to  Life.  The  Muscles  :  General 
Structure— Connective  Tissue — Parts  of  Muscles — Tendons — 
Hollow  Muscles — How  the  Muscles  act — Voluntary  and  In- 
voluntary Muscles — Flexors  and  Extensors — How  the  Muscles 


WHAT  AND    WHERE.  \i 

PAGE 

gain  Strength — The  Muscles  need  Rest — Exercise  for  Health, 
not  for  Strength.  Hygiene  of  the  Muscles.  Something 
TO  Find  Out. 

CHAPTER   VH. 

How  THE  Body  is  Able  to  Stand        .       .       .        ,    yy 

The  Need  of  a  Bodily  Frame.  The  Bones  :  Uses  of  the 
Bones — Forms  of  Bones — Structure  of  the  Bones — Materials 
of  which  the  Bones  are  made — Growth  and  Repair  of  the 
Bones — Bones  of  the  Head — Sutures  of  the  Skull — Bones  of 
the  Trunk — Bones  of  the  Arms — Bones  of  the  Legs — Bony 
Cavities  of  the  Body.  Bodily  Movements  :  How  the  Mus- 
cles move  the  Bones — How  Shocks  are  distributed.  Hygi- 
ene OF  the  Bones.    Something  to  Find  Out. 


CHAPTER   VIII. 

How  the  Body  is  Covered     .        .        .        .        .        .91 

The  Usefulness  of  the  Bodily  Covering.  The  Skin  : 
General  Structure  of  the  Skin — Layers  of  the  Skin — How  the 
Skin  is  kept  soft — How  the  Skin  casts  out  Waste  Matter — 
How  the  Skin  regulates  Heat — How  the  Skin  absorbs — 
Why  the  Skin  should  be  kept  clean — How  to  keep  the  Skin 
clean.  The  Hair:  What  it  is — How  to  keep  the  Hair 
healthy — Thinning  and  Grayness  of  the  Hair.  Clothing; 
Why  the  Body  should  be  clothed — How  the  Body  should  be 
clothed.  Hygiene  of  the  Skin.  Something  to  Find 
Out. 

CHAPTER   IX. 

How  Bodily  Motion  is  Directed 107 

Bodily  Organs  must  act  in  Harmony.  The  Nervous 
System  ;  How  the  Nerves  are  distributed — Nerve-Matter — 
The  Brain — The  Spinal  Cord — The  Ganglions — Sympathetic 
System — Use  of  the  Nerves — Direct  Nerve-Action — Reflex 
Action — Sympathetic  Action — Habit  and  Training — Exercise 
of  the  Nerves — Rest  of  the  Nerves — How  Alcohol  affects  the 
Nerves — Staggering — Effect  on  the  Mind — The  Lower  Na- 


12  WHAT  AND    WHERE. 

PAGB 

tiire  in  Control — How  Tobacco  affect^  the  Nerves — Inherit- 
ance. Hygiene  of  the  Nerves.  Something  to  Find 
Out. 

CHAPTER   X. 

How  THE  Mind  gets  Ideas  and  Expresses  Them    .  122 

Sensations — The  Need  of  Special  Senses.  The  Sense  of 
Taste  :  The  Taste  as  a  Sentinel — Flavors — Taste  not  a  Per- 
fect Guide  in  the  Choice  of  Foods.  The  Sense  of  Smell  : 
Odors.  The  Sense  of  Hearing:  Sound — Its  Production 
— The  Ear — Care  of  the  Ear.  The  Sense  of  Seeing: 
Light — Need  of  Light — The  Eye — Its  Structure— Muscles  of 
the  Eye — Action  of  Light — Care  of  the  Eye.  The  Organs 
OF  Speech  :  The  Need  of  Expression— The  Voice — Speech 
— Care  of  the  Voice.  Hygiene  of  the  Organs  of  Special 
Sense.    Something  to  Find  Out. 

CHAPTER   XI. 

Stimulants  and  Narcotics 137 

I.  Stimulants  :  Unnecessary — Injurious.    2.  Narcotics. 

What  the  Words  Mean 141 

Topical  Analysis 156 

Bones  of  the  Body 166 

Where  to  Find  Things 169 


HOW  WE  LIVE. 


CHAPTER   I. 

THE  BODY  AND  ITS  PARTS. 

IV/iy  we  should  Study  our  Bodies. 

When  we  look  at  our  bodies,  we  see  that  they 
are  made  up  of  parts.  Each  of  these  parts  has  a 
name  and  one  or  more  uses.  We  know  the  most 
common  of  these  names  and  uses ;  but,  unless  we 
have  studied  them  with  care,  there  are  many  im- 
portant and  interesting  things  about  them  that  we 
do  not  know. 

If  any  one  should  ask  us  the  name  of  the  highest 
part  of  the  body  when  standing  erect,  we  would 
answer  that  it  is  the  head.  We  could  also  tell  the 
names  and  the  uses  of  the  outer  parts  of  the  head. 
Perhaps  we  could  make  pictures  of  them. 

We  would,  likewise,  be  able  to  tell  that  the  part 
of  the  body  next  below  the  head  is  the  neck ;  that 
the  largest  part  of  the  body  is  the  trunk ;  that  the 
parts  attached  to  the  upper  portion  of  the  trunk 
are  the  arms  ;  and  that  those  attached  to  the  lower 
portion  of  it  are  the  legs. 

But,  if  some  one  should  ask  us  about  what  is 
inside  of  the  head,  neck,  or  trunk,  we  would  be  un- 


14  HOW   WE  LIVE. 

able  to  answer  from  observation,  and  we  could  not 
tell  either  the  names  or  the  uses  of  the  parts.  Yet 
each  of  these  inside  organs  has  a  work  to  do  in  the 
support  of  life ;  and  the  peculiar  work  which  each 
does  and  its  curious  way  of  doing  it  are  matters  of 
great  interest. 

When  a  bee  stings  us,  or  we  burn  our  fingers, 
we  can  tell  the  cause  of  the  pain  ;  and  we  shall  be 
careful  to  avoid  it  in  the  future.  But  when  we 
have  earache  or  headache,  we  can  not  always  tell 
the  cause.  By  the  study  of  those  parts  of  the  body 
which  we  can  not  see,  we  may  so  change  our  course 
of  conduct  as  to  avoid  many  aches  and  diseases. 

If  we  see  a  person's  tooth  broken  off,  or  his  eye 
bhnded  by  some  accident,  we  shall  never  know- 
ingly expose  ourselves  to  the  same  danger  ;  yet,  by 
want  of  knowledge,  we  may  neglect  or  abuse  our 
teeth  or  e3^es  in  such  a  way  that  they  will  be  as 
surely  destroyed  as  by  a  visible  accident. 

Most  of  the  internal  organs  are  soft  and  deli- 
cate ;  and  when  once  injured  they  are  afterward,  in 
many  cases,  weak  and  nearly  useless.  By  knowing 
what  care  they  need,  we  may  avoid  injuring  them, 
and  so  escape  pain  and  disease. 

It  is  necessary,  therefore,  that  we  should  know 
a  great  deal  about  the  parts  of  the  body.  We 
should  know  not  only  their  names  and  uses,  but 
also  what  will  make  them  stronger  or  weaker. 
Then  we  shall  know  how  to  preserve  our  health, 
and  thus  be  able  to  keep  ourselves  in  the  best  con- 
dition to  do  our  work  in  the  world. 

Looks   are   important.     We   like   to   see   good- 


THE  BODY  AND  ITS  PARTS.  15 

looking  people.  We  should  desire  to  look  well,  so 
that  our  appearance  will  please  others.  One  of  the 
most  important  elements  of  good  looks  is  health. 
A  sickly  person  loses  that  clearness  of  complexion, 
that  sparkle  of  the  eye,  and  that  elasticity  of  step 
and  vigor  of  motion  which  we  all  admire. 

By  keeping  in  health  we  also  enjoy  life  much 
better.  We  suffer  less  from  bodily  pain ;  we  see 
things  more  clearly,  and  succeed  better  in  what  we 
undertake  ;  we  can  take  care  of  ourselves,  and  thus 
avoid  becoming  a  burden  to  our  friends;  and  we 
are  more  ready  to  perform  any  duty  that  may  pre- 
sent itself.  Besides,  we  are  more  cheerful.  We  do 
not  take  gloomy  views  of  life,  and  make  ourselves 
generally  disagreeable ;  and,  while  we  are  happier 
ourselves,  we  make  others  happier  also. 

About  Parts  of  the  Body, 

The  Arms. — We  see  that  the  arms  form  a  pair, 
and  are  fastened  sidewise  to  the  trunk  just  below 
the  neck.  They  extend  in  opposite  directions,  and 
end  in  hands,  which  continue  in  the  same  direction 
as  the  arms.  The  hands  terminate  in  fingers,  and 
the  ends  of  the  fingers  are  protected  by  nails. 

The  Legs. — The  legs  are  joined  to  the  lower 
part  of  the  trunk  and  extend  downward,  ending  in 
feet,  which  are  at  right  angles  to  the  legs.  At  one 
extremity  the  foot  has  a  heel,  and  at  the  other  it 
terminates  in  toes,  which,  like  the  fingers,  are  pro- 
tected by  nails. 

The  Limbs  and  Joints. — The  arms  and  legs 
when   taken   together   are   called   limbs.     All   the 


i6 


HO  IV   WE  LIVE. 


limbs  are  attached  to  the  body  in  such  a  way  that 
they  can  move  in  every  direction.  The  point  of  at- 
tachment is  called  a  joint. 

If  we  examine  a  leg  of  mutton,  or  the  leg  of  a 
chicken,  which  we  may  have  on  the  table  at  dinner, 

we  find  in  each  a  bone 
with  a  round  head  fitting 
into  another  bone  having 
a  cup-like  cavity.  These 
bones  form  what  is  called 
the  ball-and-socket  joint. 

Such  a  joint  we  have 
at  the  shoulders  and  the 
hips,  where  the  arms  and 
the  legs  are  attached  to 
the  body.  The  sockets 
at  the  shoulders  are  not 
so  deep  as  those  at  the 
hips,  and  this  arrange- 
ment allows  the  arms 
much  greater  freedom  of  movement. 

We  see  that  a  door  is  attached  to  the  jamb  in 
such  a  way  that  it  can  swing  in  only  two  direc- 
tions, backward  and  forward.  This  kind  of  attach- 
ment is  called  a  hinge.  The  arms  at  the  elbows, 
and  the  legs  at  the  knees,  have  only  a  forward  and 
backward  movement,  and  hence  these  joints  are 
called  hinge-joints. 

The  double  or  compound  joints  at  the  wrists 
and  the  ankles  admit  of  a  great  variety  of  move- 
ments, and  are  made  up  of  several  small,  rounded 
bones  which  move  about  each  other.    The  knuckles 


Fig 


-Ball-and-socket    joint    of 
the  hip. 


THE  BODY  AND  ITS  PARTS. 


17 


2. — Hinge -joint  of 
the  elbow. 


and  the  toe-joints,  like  those  of  the  elbows  and  the 
knees,  are  hinge-joints. 

The  lower  parts  of  the  arms 
and  legs  have  also  a  turning  or 
twisting  motion,  so  that  we  can 
turn  our  hands  completely  over 
and  our  feet  in  and  out.  This 
motion  is  brought  about  in  the 
arm  by  an  arrangement  of  two 
bones  which  extend  through  the 
lower  part  of  the  limb,  and  which 
turn  about  one  another. 

Parts  of  the  Body  in  Pairs. 
— Besides  the  pairs  of  arms  and  yig. 
of  legs,  we  have  two  ears,  two 
eyes,  and  twp  cheeks.  If  we 
examine  closely,  we  shall  see  that  the  nose  has  two 
nostrils,  and  that  the  two  sides  of  the  mouth  are 
ahke  in  structure.  This  arrangement  of  the  exter- 
nal parts  of  the  body  in  pairs  makes  it  double ;  so 
that,  if  it  were  divided  by  a  line  running  down  from 
the  middle  of  the  forehead,  it  would  be  in  halves,  each 
with  the  same  parts  turned  in  opposite  directions. 

The  Bodies  of  other  Animals. — If  we  examine 
other  animals,  we  shall  see  the  same  general  plan 
of  structure — parts  in  pairs,  and  opposite  sides  alike. 
The  parts  of  other  animals  correspond  to  parts  of 
our  own  bodies  in  many  respects,  agreeing  in  num- 
ber, position,  and  general  use,  but  differing  some- 
what in  form.  Thus  the  cat  and  the  dog  have  four 
limbs  each :  but  their  arms  are  fore-legs ;  their 
hands,  paws ;  and  their  nails,  claws; 


l8  HOW  WE  LIVE. 

The  horse  and  the  cow  also  have  four  limbs 
each ;  but,  in  the  place  of  toes,  the  horse  has  a  sin- 
gle hoof,  and  the  cow  a  double  one.  The  chicken's 
arms  are  wings ;  the  bat's  four  limbs  are  connected 
by  a  thin,  delicate  skin,  forming  wings  with  which 
it  can  fly ;  the  four  limbs  terminate  in  feet,  two  of 
them  webbed  for  swimming ;  the  fish's  four  limbs 
are  fins ;  and  nearly  all  the  vertebrates  are  provided 
with  the  same  number  of  limbs,  showing  a  general 
plan  in  creation,  or,  as  Agassiz  expresses  it,  "a 
thought  of  God." 

Uses  of  the  Parts  of  the  Body. — In  each  one  of 
us  the  part  that  thinks,  or  the  mind,  is  the  most  im- 
portant. The  mind  in  thinking  makes  direct  use  of 
the  brain.  The  brain  is  in  the  head,  and  is  pro- 
tected by  the  skull. 

Every  time  the  mind  thinks,  a  tiny  part  of  the 
brain  wears  out  and  must  be  repaired.  The  ma- 
terials for  the  repair  come  from  the  blood.  Hence 
we  must  have  a  way  of  making  blood.  For  this  pur- 
pose we  have  a  trunk ;  and  this  is  large,  so  that  it 
may  contain  everything  necessary  for  the  process. 

To  make  blood,  we  must  have  food  ;  and  to  get 
food,  we  have  arms  to  reach  out  and  take  it,  and 
legs  to  go  in  search  of  it.  We  thus  see  that  all  the 
parts  are  made  expressly  for  the  service  of  the 
mind ;  and  that  by  their  proper  action  alone  can 
the  mind  be  kept  in  good  condition.  One  would 
think,  then,  that  the  mind,  if  it  is  sensible,  would 
take  good  care  of  the  body. 


THE  BODY  AND  ITS  PARTS.  19 


Something  to  Fifid  Out,  . 

1.  Why  should  we  try  to  look  as  well  as  we 
can  ? 

2.  What  are  some  of  the  things  necessary  to 
good  looks  that  we  all  can  attend  to  ? 

3.  Which  of  the  ball-and-socket  joints  are  most 
easily  put  out  of  joint  ?     Why  ? 

4.  What  kind  of  joint  unites  the  thumb  to  the 
hand? 

5.  How  many  joints  have  the  fingers  ?  the  toes? 

6.  How  does  the  great-toe  differ  from  the  thumb? 

7.  How  does  the  ankle  differ  from  the  wrist? 

8.  How  do  the  cat's  toes  correspond  in  number 
to  our  fingers  and  toes  ? 

9.  How  do  the  cat's  fore-paws  differ  from  our 
hands  ? 

10.  What  joint  in  the  dog's  hind -legs  corre- 
sponds to  our  hips  ?  knees  ?  ankles  ? 

11.  What  bone  in  the  cat's  leg  represents  our 
heel? 

12.  On  what  part  of  the  foot  do  we  tread?  On 
what  part  does  the  dog  tread  ? 

13.  Explain  what  is  meant  by  the  term  digiti- 
grade — plantigrade. 

14.  Give  two  examples  of  digitigrade  animals — 
of  plantigrades. 

15.  To  which  of  these  classes  does  the  horse 
belong?  the  cow?  the  sheep?  the  bear?  the  ele- 
phant ? 

16.  Why  are  the  bones  of  the  skull  made  very 
strong  ? 


20  ^OW   WE  LIVE. 

17.  What  animals  use  their  fore-paws  to  hold 
their  food  while  eating  ? 

18.  How  does  the  duck's  foot  differ  from  that 
of  a  chicken  ? 

19.  What  do  birds  have  in  the  place  of  mouth 
and  nose  ? 

20.  In  what  way  can  we  best  avoid  mistakes  in 
taking  care  of  the  body  ? 


Note. — At  the  latter  end  of  the  book,  commencing  on  page  156, 
will  be  found  a  topical  analysis  for  each  general  subject  treated  in  the 
several  chapters.  These  outline  statements  may  be  made  of  great 
value  to  teacher  and  pupil,  as  showing  the  relations  of  the  topics  and 
sub-topics  to  each  other,  and  as  affording  a  scientific  basis  for  exami- 
nations and  reviews. 


CHAPTER  II. 

EATING,   AND  WHAT  COMES  OF   IT. 

W/ij^  we  Eat, 

Every  motion  that  we  make,  and  every  thought 
that  we  think,  destroys  some  of  the  minute  cells  of 
which  the  various  parts  of  the  body  are  composed. 
If  this  waste  goes  on  without  repair,  the  parts  soon 
wear  out,  and  the  body  dies.  The  process  of  re- 
pair is  called  nurture,  and  the  elements  of  nurture 
are  found  in  food. 

Before  the  food  can  nurture  the  body,  it  must 
undergo  many  changes.  It  must  be  broken  up ; 
parts  of  it  must  be  dissolved  ;  different  parts  must 
be  mixed  with  each  other;  and  the  useful  parts 
must  be  separated  from  those  which  are  worthless. 
The  first  step  in  this  process  is  eating.  We  eat, 
then,  that  we  may  live.  We  eat,  that  every  part  of 
our  bodies  may  be  strengthened,  and  that  we  may 
be  able  to  do  our  daily  work. 

What  we  Eat. 

Upon  our  tables,  for  breakfast  or  dinner,  we 
have  meat,  bread,  potatoes,  fish,  fruit,  and  many 
other  articles  of  food  to  eat ;  and  water,  milk^  and 


22  HOW   WE  LIVE. 

other  liquids  to  drink.*  We  must  take  this  food 
and  drink  at  regular  times,  to  satisfy  the  demands 
of  appetite  and  the  needs  of  the  system. 

As  the  body  is  composed  of  many  different  ele- 
ments, the  food  and  drink  which  we  take  must  con- 
tain these  elements.  If  we  take  no  food,  we  starve ; 
if  we  take  food  that  lacks  some  needed  element, 
after  a  time  we  starve  just  as  certainly. 

More  of  the  elements  which  the  body  needs  are 
found  in  some  articles  of  food  than  in  others.  But, 
as  no  one  food  contains  all  kinds  and  sufficient 
quantities  of  needed  elements,  we  are  obliged  to 
take  a  variety  of  foods — one  kind  furnishing  the 
elements  which  the  others  lack. 

Kinds  of  Food. — One  of  the  most  valuable  of  all 
the  foods  is  the  gluten,  or  sticky  part,  of  flour.  It 
contains  all  the  elements  which  the  body  needs,  but 
not  all  of  them  in  sufficient  quantity.f  Nearly  the 
same  elements  are  found  in  the  albumen,  or  white, 

*  The  pupil  should  here  enumerate  the  different  kinds  of  food  in 
common  use,  and  find  out  all  he  can  about  each.  For  example  :  bread 
is  made  of  wheat  ;  the  wheat  grows  in  our  fields  ;  the  grain  is  taken 
to  the  mill  and  ground  ;  and  the  meal  or  flour  is  made  into  bread.  This 
treatment  of  the  subject  serves  to  introduce  both  farming  and  manu- 
facturing operations,  and  to  show  their  relation  to  our  needs. 

Again,  take  rice,  another  common  article  of  food.  This  grain  does 
not  grow  in  our  fields,  but  is  the  product  of  a  warm,  lowland  region. 
The  description  of  its  place  and  manner  of  growth  serves  to  show  the 
relations  of  food  to  geography,  and  to  give  a  new  and  vital  interest  to 
that  branch  of  study.  In  like  manner,  tea,  coffee,  sugar,  salt,  and  many 
othei  articles  may  be  made  to  serve  a  similar  purpose 

f  Wheat,  the  most  valuable  of  our  grains,  contains  a  large  amount 
of  gluten.  Fine  white  flour  contains  little  gluten,  and,  when  we  make 
bread  of  it,  we  lose  the  best  part  of  the  grain.  The  "  new-process  " 
flour  retains  the  gluten,  and  makes  excellent  bread. 


EATING,  AND   WHAT  COMES  OF  IT         23 

of  ^gz^\  in  the  myosin,  which  is  the  principal  part 
of  lean  meat;  in  the  caseine,  or  curds,  of  which 
cheese  is  made  ;  and  in  the  fibrine  which  constitutes 
the  clot  of  the  blood.  These  foods  are  known  as 
proteids,  or  albuminoids. 

Another  substance  of  great  value  as  food  is  the 
starch  that  forms  a  large  part  of  the  grains  and 
other  vegetable  products.  Starch  does  not,  how- 
ever, contain  so  many  of  the  needed  elements  as 
gluten,  and  is  therefore  less  valuable  as  food.  The 
same  elements  in  differing  proportions  are  found  in 
sugar  and  in  the  vegetable  gums.  These  foods  are 
known  as  amyloids y' 

The  third  class  of  foods  includes  all  oily  sub- 
stances, both  animal  and  vegetable,  and  are  known 
as  fats.  They  are  composed  of  the  same  elements 
as  starch  and  sugar,  but  they  so  differ  in  form  that 
they  need  a  different  treatment  before  they  can 
nourish  the  body.f 

Minerals  form  the  fourth  class  of  substances  that 
may  be  ranked  as  foods.  They  include  lime,  soda, 
potash,  iron,  salt,  and  water.     These  are  all  found 

*  Starch  forms  a  large  part  of  all  the  grains.  Potatoes  contain  but 
little  besides  starch  and  water.  Peas  and  beans  are  more  than  half 
starch.  Tapioca,  sago,  arrowroot,  and  rice  are  nearly  all  starch.  Beets, 
turnips,  and  other  garden  vegetables  are  principally  made  up  of  starch, 
sugar,  and  water. 

f  All  the  kinds  of  food  given  above  not  only  furnish  the  elements 
of  nurture,  but  each  helps  to  furnish  the  heat  necessary  for  the  well- 
being  of  the  body.  But,  while  the  proteids  are  best  for  nurture,  the 
sugars  and  the  starches  are  also  needed.  The  amyloids  have  great 
power  of  producing  heat,  but  the  fats  have  still  greater.  In  the  frozen 
regions  of  the  extreme  north,  oil  is  one  of  the  most  necessary  articles 
of  diet. 


24  ffOlV   WE  LIVE. 

in  the  body,  and  must  be  contained  in  the  different 
articles  of  food.  These  substances,  with  the  excep- 
tion of  salt,  are  found  in  sufficient  quantities  in  meat, 
in  fruit,  and  in  vegetables. 

Special  Foods. — Of  the  vegetable  foods,  Avheat- 
flour  and  oatmeal  contain  the  greatest  number  of 
needed  elements,  and  come  the  nearest  to  perfect 
foods.  Corn-meal  is  rich  in  starch  and  fats,  but  has 
little  gluten.  Peas  and  beans  have  a  large  portion 
of  vegetable  caseine,  a  substance  that  resembles  glu- 
ten, and  they  are  ranked  very  high  as  foods.  As 
they  are  not  easily  digested,  however,  they  should 
be  taken  only  in  small  quantities  by  those  who  have 
weak  stomachs.* 

Beef  is  the  best  of  all  the  kinds  of  meat.  Next 
to  this  comes  mutton.  Chicken  and  turkey  have 
nearly  the  same  elements,  with  the  exception  of  the 
fats.  Veal,  lamb,  and  pork  have  less  of  the  elements 
which  the  body  needs,  and  are  harder  to  digest. 
Eggs  and  milk  are  nearly  perfect  foods.  Fish  and 
oysters  are  among  the  best  of  foods.  Clams,  crabs, 
and  lobsters  are  less  easily  digested. f 

*  Graham-flour,  containing  the  whole  of  the  wheat-grain,  makes 
sweet  and  wholesome  bread.  Rolls  made  of  this  flour,  by  simply  mix- 
ing the  flour  with  water  or  milk,  and  then  pouring  the  thin  batter  into 
a  hot  roll-pan,  and  baking  in  a  hot  oven,  are  among  the  best  forms  of 
bread  that  can  be  made.  The  garden  vegetables  generally  are  made 
up  of  starch  and  sugar  and  a  large  amount  of  water. 

f  Meats  are  best  when  broiled  or  roasted.  They  should  be  exposed 
to  a  hot  fire  at  first,  so  that  a  crust  may  be  formed  on  the  outside  to 
preserve  the  inside  juices. 

In  making  soups,  the  meat  should  be  put  in  cold  water,  and  brought 
very  slowly  to  the  boiling-point,  so  as  to  extract  the  juices. 


EATING,  AND    WHAT  COMES  OF  IT.         25* 

Fruits  are  mostly  made  up  of  starch  and  sugar, 
but  they  also  contain  more  of  the  mineral  matter 
needed  by  the  system  than  is  found  in  most  other 
foods.  The  acid  of  fruits  is  also  an  aid  to  diges- 
tion. Fruits  are  chiefly  valued,  however,  for  their 
agreeable  flavors,  which  gently  excite  the  digestive 
organs  ;  and  when  taken  in  moderate  quantities  they 
are  very  wholesome.^ 

Mixed  Foods. — Our  study  so  far  has  shown  us 
that  no  one  substance  is  a  perfect  food,  and  there- 
fore that  a  mixture  of  foods  is  necessary  to  secure 
all  the  needed  elements.  Experience  has  taught  us 
the  same  lesson,  and  the  custom  is  general  of  mix- 
ing foods  in  such  a  way  that  one  will  supply  the 
needed  elements  which  the  others  lack.  Thus 
bread,  rich  in  gluten,  lacks  starch  or  fat,  and  butter 
is  added  ;  potatoes,  mostly  starch,  are  eaten  with 
meat,  gravy,  or  butter. 

How  we  Eat. 

Mastication.— The  first  step  toward  reducing 
food  to  a   condition   in  which  it  can  nourish  the 

When  milk  produces  an  unpleasant  effect  upon  the  stomach,  it 
should  be  mixed  with  a  little  lime-water. 

Fish  and  oysters  should  not  be  eaten  unless  perfectly  fresh. 

*  Strawberries,  raspberries,  blackberries,  currants,  cherries,  peaches, 
apples,  melons,  and  oranges  are  all  excellent,  and  their  moderate  use, 
each  in  its  season,  will,  many  times,  make  the  doctor's  visit  unneces- 
sary, and  save  us  from  a  course  of  medicine. 

The  puipy  substance  of  unripe  fruits  is  often  hard  and  tough,  and 
the  juice  strong  and  sour.  When  fruits,  in  this  condition,  are  eaten, 
they  can  not  be  digested,  and  both  pulp  and  juice  cause  irritation  and 
often  inflammation  of  the  digestive  organs.  Fruits  are  made  whole- 
some by  ripening  and  by  cooking. 


26  HOPV   WE  LIVE. 

body  is  chewing,  or  mastication.  The  organs  di- 
rectly used  in  chewing  are  the  teeth,  the  tongue, 
and  the  cheeks.  The  teeth  grind  the  food.  The 
tongue  and  the  cheeks  keep  the  food  between  the 
teeth  so  that  it  may  be  ground. 

The  Teeth. — If  we  examine  the  mouth  of  a  cat 
or  a  dog,  we  discover  four  prominent  teeth  that  are 
long  and  pointed.  The  other  teeth,  both  front  and 
back,  are  shorter  and  smaller.  These  sharp  teeth 
can  easily  pierce  soft  substances,  and  seem  to  be  of 
just  the  right  shape  for  tearing  flesh. 

In  the  mouth  of  a  squirrel  or  rabbit  we  find  the 
prominent  teeth,  four  in  number,  directly  in  front. 
These  teeth  are  long ;  but,  instead  of  being  pointed, 
they  have  a  sharp  edge  like  a  chisel,  which  fits  them 
for  cutting  hard  substances  or  gnawing. 

If  we  look  into  the  mouth  of  a  horse,  we  find  the 
prominent  teeth  broad  and  flat,  the  exact  shape  for 
grinding  grain,  or  for  breaking  in  pieces  the  soft 
stalks  of  plants. 

In  our  own  mouths  we  find  teeth  like  those  of 
the  dog,  the  rabbit,  and  the  horse ;  but  they  are  all 
nearly  alike  in  size.  The  four  cutting  teeth  on  each 
jaw  in  front  are  called  incisors ;  the  four  pointed 
teeth,  one  on  each  side  of  each  jaw,  next  back  of 
the  incisors,  are  called  ca?iine  teeth,  or  cuspids ;  the 
eight  teeth  next  to  the  cuspids  are  the  bicuspids  ; 
and  the  twelve  back  teeth,  six  on  each  jaw,  are 
molars. 

The  parts  of  the  teeth  that  lie  inside  the  bones 
of  the  jaw  are  the  roots,  and  the  part  of  each  tooth 
that  appears  outside  the  gums  is  the  crown.     Usu- 


EATING,  AND    WHAT  COMES  OF  IT.         27 

ally,  the  molars  of  the  upper  jaw  have  three  roots 
each,  and  those  of  the  lower  jaw  have  two.  The 
cuspids  and  incisors  have  only  one  root  each. 


-  —   b 


d 

Fig.  3. — The  jaws  and  the  teeth  :  i,  2,  incisors ;  3,  canines ;  4,  5,  bicus- 
pids ;  6,  7,  8,  molars ;  a,  vein  ;  ^,  artery  ;  c^  nerve  ;  d^  vein,  artery,  and 
nerve. 

If  we  carefully  examine  a  tooth,  we  find  that  the 
crown  has  a  hard,  smooth  outside.  This  is  called 
the  enamel.  Under  the  enamel  is  a  softer  kind  of 
bone  called  dentine.  In  the  middle  of  the  tooth,  and 
extending  to  the  end  of  each  root,  is  a  cavity  in  the 
bone,  through  which  extend  a  nerve  and  a  net-work 
of  blood-vessels. 


28 


I/O IV    WE  LIVE. 


Fig.  4. — Section  of  a  tooth 
Ay  enamel ;  B,  nerve  cav- 
ity ;  C,  C,  roots. 


Care  of  the  Teeth. — When  the  enamel  is  broken 
the  tooth  decays,  causing  severe  pain  and  an  un- 
pleasant breath.  To  prevent 
these  troubles,  the  teeth 
should  receive  special  and 
constant  care. 

Some  boys  try  to  crack 
hard  nuts  with  their  teeth,  but 
crack  the  enamel  instead,  and 
so  spoil  their  teeth.  Biting 
hard  substances  of  any  kind 
has  the  same  effect. 

A  pitcher  when  cold  may 
be  easily  cracked  by  pouring 
into  it  a  stream  of  hot  water. 
The  sudden  and  irregular  change  of  temperature 
causes  the  break.  In  like  manner  the  enamel  of  the 
teeth  may  be  cracked  by  abruptly  changing  from 
cold  to  hot  foods,  as  from  ice-cream  to  hot  tea. 

When  food  gets  lodged  between  the  teeth  and  is 
permitted  to  remain  there,  a  kind  of  gas  is  formed 
which  destroys  the  enamel  and  causes  the  whole 
tooth  to  decay. 

How  to  keep  the  Teeth  Clean. — After  each 
meal,  the  food  lodged  between  the  teeth  should  be 
carefully  removed  by  a  tooth-pick  of  wood  or  quill. 
The  use  of  a  pin  or  a  penknife  is  apt  to  injure  the 
teeth  or  the  gums.  On  rising  in  the  morning,  after 
each  meal,  and  before  going  to  bed  at  night,  the  teeth 
should  be  cleaned  with  water  and  a  tooth-brush.* 

*  The  tooth-brush  should  be  stiff  enough  to  remove  all  food  from 
the  teeth,  but  not  so  stiff  as  to  injure  the  gums. 


EATING,  AND    WHAT  COMES  OF  IT. 


29 


A  little  fine  salt  may  sometimes  be  used  with  profit. 
Powdered  orris-root,  used  sparingly,  will  help  to 
keep  the  breath  sweet. 

A  hard  substance,  known  as  tartar,  sometimes 
collects  on  the  inside  of  the  teeth,  next  the  gums, 
and,  if  permitted  to  remain,  will  destroy  both  teeth 
and  gums.  When  it  begins  to  collect,  this  tartar 
may  be  readily  removed  by  scraping  the  teeth  with 
the  broad  end  of  a  quill  tooth-pick. 

How  we  Swallow. 

After  the  food  has  been  chewed  enough,  it  is  to 
be  swallowed.  Before  swallowing,  saliva  is  mixed 
with  it,  moistening  it,  and  making  it  slippery,  so 
that  it  will  go  down  easily.  The  saliva  is  furnished 
by  the  salivary  glands  of  the  mouth,  and  is  obtained 
from  the  blood. 

How  Saliva  Flows. — The  salivary  glands  do  not 
pour  out  saliva  all  the  time,  but  are  excited  to  ac- 
tion in  various  ways. 

The  movement  of  the  jaws  will  produce  a  flow 
of  saliva.  In  chewing,  this  flow  is  enough  to  moist- 
en the  food,  and  in  talking  it  is  usually  suflicient  to 
keep  the  mouth  moist. 

Touching  any  part  of  the  mouth,  or  the  presence 
of  anything  in  it,  will  cause  the  saliva  to  flow,  as 
every  one  knows  who  has  been  under  the  hands  of 
the  dentist. 

The  sight,  smell,  or  taste  of  food  when  we  are 
hungry  will  also  *'  make  the  mouth  water."  This 
may  be  seen  by  watching  a  cow  when  she  is  look- 
ing on  while  her  supper  of  turnips  is  in  course  of 


30 


HOW    WE  LIVE. 


preparation.  The  saliva  is  produced  in  such  quan- 
tities as  to  flow  out  of  the  corners  of  her  mouth. 

Articles  of  a  pungent  taste,  like  mustard,  pep- 
per, horse-radish,  and  tobacco,  make  the  mouth 
hot,  causing  a  free  flow  of  saliva. 

Amount  of  Saliva. — We  need  just  enough  saliva 
to  moisten  our  food.  When  we  do  not  get  enough, 
we  find  it  difficult  to  swallow,  and  then  there  is 
trouble  in  the  stomach.  To  get  this  amount  takes 
time.  Those  who  eat  hastily,  and  bolt  their  food 
without  chewing,  may  look  forward  to  a  time  when 
they  can  not  eat  with  any  comfort,  and  when  they 
will  have  no  strength  for  work,  or  play,  or  enjoy- 
ment of  any  kind. 

We  need  to  eat  slowly  and  chew  our  food  very 
fine,  so  that  the  movement  of  the  jaws  will  cause 
enough  saliva  to  pour  out.  Bread  and  vegetable 
foods  need  more  chewing  than  meats. 

All  flow  of  saliva  in  excess  of  the  amount  needed 
for  the  moistening  of  the  food  and  the  mouth  is 
waste.  The  blood  from  which  it  comes  is  made 
thinner  and  poorer,  and  has  less  of  the  materials 
necessary  for  the  repairs  of  the  body. 

How  Saliva  is  Wasted. — If  we  keep  our  jaws 
in  motion  when  we  are  not  eating,  a  useless  flow  of 
saliva  is  produced,  which  is  waste  of  material  and 
weakening  to  the  body.  Chewing  gum  and  all  like 
habits  are  therefore  hurtful. 

Tobacco. — The  most  fruitful  cause  of  waste  in 
saliva,  however,  is  the  use  of  tobacco.  The  pun- 
gent qualities  of  this  narcotic  produce  an  excessive 
flow,  and,  when  the  exciting  cause  is  constantly  kept 


EATING,  AND   WHAT  COMES  OF  IT.         31 

Up,  the  amount  wasted  often  becomes  serious  and 
exhaustive. 

Again,  by  this  waste  the  materials  of  the  blood 
by  which  saliva  is  furnished  gradually  diminish. 
The  saliva  itself  becomes  weak,  inactive,  and  unable 
to  perform  its  special  work  in  the  stomach ;  and, 
besides,  other  materials  needed  elsewhere  are  con- 
tinually drained  off. 

,  One  other  effect  of  the  use  of  tobacco  needs  to 
be  mentioned  here.  It  gives  an  unpleasant  odor  to 
the  breath,  and  often  causes  a  disagreeable  habit  of 
spitting ;  so  that  clean,  sensitive,  and  refined  persons 
do  not  like  to  have  those  who  use  tobacco  come 
near  them. 

The  Esophagus.  —  The  esophagus  is  the  tube 
through  which  the  food  passes  from  the  mouth  to 
the  stomach.  When  the  food  is  sufficiently  chewed 
and  moistened,  it  is  pressed  backward  by  the 
tongue,  and  falls  into  the  pharynx^  a  portion  of 
the  throat  which  lies  immediately  above  the  esoph- 
agus. 

On  its  way  to  the  pharynx  it  passes  over  the  en- 
trance of  the  windpipe,  but  is  kept  from  falling  into 
it  by  the  epiglottis,  a  valve  which  shuts  down  when 
the  food  comes  along.  Sometimes  the  epiglottis 
does  not  close  quickly  enough,  and  a  particle  of 
food,  getting  into  the  windpipe,  chokes  us,  and 
causes  us  to  cough  until  it  is  thrown  out.  By  eat- 
ing slowly  we  avoid  this  danger. 

Muscles  extend  around  the  esophagus,  and  when 
the  food  enters  from  the  pharynx  they  contract,  the 
upper  one  first,  and  then  the  next  in  order,  thus 


32  ^OIV    WE  LIVE, 

gradually  forcing  the  food  into  the  stomach.  The 
process  of  eating  is  now  done,  and  that  of  digestion 
is  ready  to  proceed. 

Hygiene  of  Mastication. 

From  the  foregoing  study  of  the  subject  we  de- 
rive  the  following  laws  in  regard  to  mastication : 

I.  Take  food  that  will  best  nourish  the  body. 

II.  Eat  slowly,  to  give  the  time  necessary  for  the 
proper  action  of  all  the  organs  of  mastication. 

III.  Chew  food  until  enough  saliva  is  obtained 
to  moisten  it. 

IV.  Do  not  injure  the  teeth  by  biting  hard  sub- 
stances. 

V.  Avoid  exposing  the  teeth  to  sudden  changes 
of  temperature. 

VI.  Keep  the  teeth  clean. 

VII.  Swallow  slowly,  so  as  to  give  the  epiglottis 
time  to  act,  and  thus  avoid  choking. 

VIII.  Be  sparing  in  the  use  of  highly  seasoned 
foods  that  induce  too  great  a  flow  of  saliva. 

IX.  Do  not  keep  the  jaws  in  motion  by  chewing 
gum  and  other  substances  not  needed  as  food. 

X.  Avoid  the  use  of  tobacco,  as  it  wastes  saliva, 
weakens  the  body,  and  makes  the  person  using  it 
disagreeable. 

Something  to  Find  Out. 

1.  What  other  grains  besides  wheat  are  raised 
on  our  farms  ? 

2.  What  garden  vegetables  do  we  raise  to  eat  ? 

3.  What  part  of  the  corn-plant  do  we  eat  ?  of  the 


EATING,  AND    WHAT  COMES  OF  IT.         33 

potato-plant  ?  of  the  beet  ?  of  the  onion  ?  of  aspara- 
gus ?  of  cabbage  ? 

4.  What  substance  in  dough  makes  it  stick  to- 
gether ? 

5.  How  is  wheat-bread  made  Hght? 

6.  Why  is  it  more  difficult  to  make  corn-bread 
light?  In  making  corn-bread,  what  is  the  effect  of 
mixing  the  white  of  eggs  with  the  corn-meal  ? 

7.  Why  is  fat  meat  more  eaten  in  winter  than  in 
summer? 

8.  How  is  the  oil  necessary  for  food  obtained  in 
the  frozen  regions  ? 

9.  Why  is  more  wholesome  food  made  from 
Graham-flour  than  from  fine  white  flour  ? 

10.  Why  is  beef  as  a  food  better  than  pork? 

11.  Why  are  oysters  better  than  clams? 

12.  Why  is  it  better  to  roast  beef  than  to  boil  it? 

13.  In  boiHng  meats,  should  they  be  put  into 
cold  or  hot  water  at  first  ? 

14.  In  what  condition  should  oysters  and  fish  be 
when  used  for  food  ? 

15.  Of  what  benefit  is  the  acid  of  fruits? 

16.  Why  are  green  fruits  unwholesome? 

17.  How  may  green  fruits  be  made  wholesome? 

18.  What  kind  of  food  should  be  mixed  with 
the  proteids  ?     What  with  the  amyloids  ? 

19.  In  cooking,  what  is  usually  mixed  with  maca- 
roni ?     Why  ? 

20.  Mention  other  foods  that  are  usually  eaten 
together. 

2 1 .  What  are  milk-teeth,  and  what  care  do  they 
need  ? 


34 


HOW    WE  LIVE. 


22.  When  the  permanent  teeth  show  signs  of 
decay,  what  should  we  do  ? 

23.  Why  should  we  be  sparing   in  the  use  of 
mustard  and  horse-radish  ? 

24.  When  people  know  that  the  use  of  tobacco 
is  hurtful,  why  do  they  not  leave  it  off? 

25.  What  is  the  best  way  to  avoid  the  trouble  of 
leaving  off  the  use  of  tobacco  ? 

26.  What  evils  follow  from  eating  too  rapidly  ? 


CHAPTER   III. 

HOW   DIGESTION   GOES   ON. 

To  nourish  the  body,  food  taken  into  the  stom- 
ach must  be  converted  into  blood.  The  process  of 
preparing  food  to  enter  the  blood,  called  digestion, 
takes  place  chiefly  in  the  stomach  and  intestines. 

Stomach  Digestion. 

Structure.  — The  stomach  is  a  sack  or  bag  in  the 
lower  cavity  of  the  body,  and  holds  from  one  to  two 
quarts.^     It  has  two  openings.     Through  the  up- 


FiG.  5. — The  stomach. 

*  The  trunk  has  two  cavities,  the  chest  and  the  abdomen.     These 
cavities  are  separated  by  a  thick,  muscular  membrane,  called  the  dia- 

3 


36  HOW   WE  LIVE. 

per  opening,  or  cardiac  the  food  comes  in  Irom  the 
esophagus ;  and  through  the  lower  opening,  or 
pylorus,  the  food,  when  in  a  proper  condition,  passes 
out  into  the  intestines. 

The  stomach  is  made  up  of  three  coats.  The 
outer,  or  serous,  coat  is  strong  and  smooth.  Its 
glossy  surface  is  moistened  by  the  serum  from  the 
blood,  so  that,  when  it  rubs  against  the  walls  of  the 
trunk,  or  against  any  of  the  other  organs,  there  is 
no  friction. 

The  middle  coat  is  made  up  of  muscles,  which 
extend  around  the  stomach  in  both  the  longest  and 
shortest  ways.  These  muscles  contract  and  ex- 
pand, giving  motion  to  the  stomach,  and  churning 
its  contents. 

The  inner,  or  mucous,  coat  is  soft,  and  lies  in 
little  ridges  or  folds,  giving  a  great  amount  of  sur- 
face. This  coat  secretes  from  the  blood  a  fluid, 
known  as  the  gastric  juice,  which  flows  in  large 
quantities  when  the  stomach  is  full.  The  churning 
process  brings  the  gastric  juice  into  contact  with 
the  food,  and  thoroughly  mixes  the  contents  of  the 
stomach. 

Food  Changes. — The  saliva,  mixed  with  the 
food,  is  one  of  the  agencies  for  changing  the  amy- 
loids into  grape-sugar — a  process  necessary  to  fit 
these  substances  to  enter  the  blood. 

The  gastric  juice  dissolves  the  proteids,  such  as 
the  albumen  of  eggs,  the  gluten  of  grain,  and  the 
fibrine  of  meat,  and  makes  them  fit  to  enter  the  blood. 

phragm.  This  membrane  is  attached  to  the  walls  of  the  trunk,  and 
forms  the  floor  of  the  chest  and  the  roof  of  the  abdomeri. 


HOW  DIGESTION  GOES  ON. 


11 


A  small  portion  of  the  food  is  taken  up  from  the 
stomach  by  capillaries,  called  absorbents,  and  carried 
at  once  to  the  portal  vein.  But  by  far  the  greater 
part  is  converted  into  a  slimy,  fluid  mass,  called 
chyme,  and  passes  through  the  pylorus  into  the  in- 
testines. 

Drink. — At  each  meal  enough  drink  should  be 
taken  with  the  solid  food  to  moisten  the  mass  in  the 
stomach.  If  too  much  is  taken,  the  gastric  juice  is 
so  diluted  and  weakened  that  it  can  not  properly 
perform  its  work. 

For  the  action  of  the  mucous  and  muscular  coats 
of  the  stomach,  and  of  the  absorbents,  the  animal 
heat  must  be  kept  up.  By  drinking  ice-water,  or 
any  very  cold  drinks,  with  our  meals,  the  heat  is 
diminished,  and  the  work  of  digestion  goes  on 
slowly,  or  not  at  all,  until  the  heat  is  restored. 

Alcohol  in  the  Stomach. — When  stimulants  con- 
taining alcohol  are  taken  into  the  stomach,  the  first 
effect  is  to  excite  the  mucous  coat,  and  increase 
the  flow  of  the  gastric  juice.  If  the  drink  is  con- 
tinued from  day  to  day,  the  gastric  flow  increases, 
and  is  excessive.  In  consequence,  it  becomes  thin 
and  weak,  and  is  unable  to  perform  its  proper  work 
of  digestion. 

But  alcohol  has  a  great  power  of  absorbing 
water.  It  takes  moisture  out  of  the  mucous  coat 
of  the  stomach.  By  continually  drinking  it,  the 
stomach  becomes  hardened,  and  is  unable  to  supply 
gastric  juice  enough  for  digestion.  If  the  drinking 
is  then  kept  up,  more  or  less  active  inflammation 
always  sets  in,  often  causing  long  illness,  or  death. 


38  1^0  IV    WE  LIVE. 

Alcohol  has  another  peculiar  effect.  Its  action  on 
the  stomach  often  leaves  a  sickly,  sinking  sensation, 
which  can  be  relieved  only  by  alcohol ;  and  so 
drink  induces  drink,  until  the  habit  is  formed  from 
which  no  one  can  escape  without  great  suffering. 

While  the  alcohol  is  busy  with  its  work  in  the 
stomach,  the  absorbents  are  trying  to  get  rid  of  it. 
They  take  it  up  unchanged,  and  pass  it  on  into  the 
blood-vessels,  ready  to  repeat  elsewhere  the  mis- 
chief it  has  begun  in  the  stomach. 

Intestinal  Digestion. 

Structure. — The  intestines  are  tubes  lying  in  a 
coil,  through  which  the  food  passes  after  leaving 
the  stomach.  The  small  intestine  is  about  one  inch 
in  diameter  and  twenty  feet  long.  The  large  intes- 
tine is  twice  as  large,  and  five  feet  in  length.  This 
gives  to  the  whole  canal  below  the  stomach  a  length 
of  about  twenty-five  feet. 

Like  the  stomach,  the  intestines  have  three  coats, 
serous,  muscular,  and  mucous.  The  mucous  coat 
secretes  from  the  blood  and  pours  out  in  small 
quantities  the  intestinal  juices.  These  mix  with  the 
chyme  coming  from  the  stomach,  and  convert  into 
sugar  a  portion  of  the  starch  which  has  before  es- 
caped digestion. 

The  muscular  coat  of  the  intestines  consists 
mostly  of  rings,  and  these,  beginning  with  the  one 
nearest  the  stomach,  contract,  one  after  the  other, 
like  those  of  the  oesophagus.  This  action  forces  the 
contents  downward,  and  finally  expels  the  waste 
portion  from  the  body. 


HOW  DIGESTION  GOES  ON. 


39 


/  k       j 

Fig.  6. — The  organs  of  digestion  :  a,  duodenum,  leading  out  of  the  pylorus; 
^,  liver  ;  r,  esophagus  ;  d,  pancreas  ;  e^  stomach  ;  /,  spleen  ;  g^  t\  j\  k,  w, 
«,  parts  of  large  intestine  ;  //,  /,  small  intestine. 


The  Duodenum. — The  upper  part  of  the  small 
intestine,  about  twelve  finger-breadths  in  length,  is 
called  the  duodenum.  The  chyme  enters  this  canal 
from  the  stomach,  and  on  its  passage  receives  two 
fluids  known  as  pancreatic  juice  and  bile^  and  these 
still  further  prepare  the  food  for  the  nurture  of  the 
body. 

The  Pancreas. — The  pancreas  is  an  organ  lying 
back  of  the  stomach,  irregular  in  shape  and  about 


40  HOW  WE  LIVE. 

six  inches  long."^  It  secretes  pancreatic  juice  from 
the  blood,  and  pours  it  out  into  the  duodenum  to 
mix  with  the  chyme.  The  pancreatic  juice  is  al- 
kaline, and  neutralizes  acids.  It  also  acts  upon  un- 
digested amyloids,  proteids,  and  fats. 

When  the  chyme  enters  the  duodenum,  the  oily 
portion  lies  on  the  surface.  The  pancreatic  juice 
unites  with  it  and  divides  it  into  minute  particles 
and  mixes  it  through  the  whole  mass  of  chyme,  as 
the  oily  particles  of  cream  are  divided  and  mixed 
in  milk.  A  part  of  the  oil  is  converted  into  a  sub- 
stance resembling  soap. 

The  Liver. — The  liver  is  a  large  organ  lying  on 
the  right  side  under  the  lower  ribs.  It  secretes 
bile  from  the  blood  and  pours  it  out  into  the  duo- 
denum. The  portion  of  the  food  taken  up  by  the 
absorbents  and  carried  to  the  veins  passes  through 
the  liver.  In  the  liver-cells  a  sugary  substance 
called  glycogen  is  secreted,  and  conveyed  by  the 
hepatic  veins  into  the  general  circulation. 

The  office  that  bile  has  to  perform  is  not  fully 
understood.  That  it  is  waste  matter  which  the 
blood  must  get  rid  of,  is  shown  by  the  fact  that, 
when  resorption  of  the  bile  takes  place,  the  body 
becomes  yellow  with  jaundice.  It  is  pretty  well  un- 
derstood that  the  bile  assists  the  pancreatic  juice  in 
reducing  fats  ;  that  it  supplies  alkali  to  neutralize 
the  acid  of  the  chyme ;  and  that  it  stimulates  in 
the  intestines  a  mucous  secretion  which  lubricates 
them  and  renders  the  passage  of  waste  matter  easy. 

*  In  animals  whose  flesh  we  eat,  the  pancreas  is  called  sweet-bread, 
and  is  considered  a  great  delicacy  for  the  table. 


HOW  DIGESTION  GOES  ON, 


41 


Alcohol  in  the  Liver.  —  The  alcohol  expelled 
from  the  stomach  makes  its  next  appearance  in  the 
liver,  whither  it  is  carried  through  the  portal  vein. 
Here,  if  continued  from  day  to  day,  it  also  changes 
the  tissue,  so  that  the  work  of  the  liver  is  imper- 
fectly done  or  suspended  altogether.  If  the  drink 
is  then  kept  up,  inflammation  often  sets  in,  causing 
much  suffering  and  frequently  ending  in  death. 
From  the  liver  the  alcohol  passes  unchanged  into 
the  veins. 

Absorption. — By  the  action  of  the  pancreatic 
juice,  and  the  bile  in  the  duodenum,  the  chyme  is 
converted  into  a  milky  substance  called  chyle,  and 
continues  its  way  through  the  intestines.  In  its 
passage,  the  portions  fit  to  make  blood  are  taken 
up  by  the  absorbents  and  lacteals  and  are  carried  to 
the  veins. 

The  mucous  coat  of  the  stomach  and  the  intes- 
tines is  covered  with  a  net-work  of  minute  veins, 
and  into  these  a  portion  of  the  food  is  carried 
directly.  These  veins  all  empty  into  the  portal 
vein,  which  terminates  in  the  liver.  After  a  change 
effected  by  the  liver,  through  the  hepatic  veins,  this 
material  is  poured  into  the  large  vein  ascending 
from  the  lower  extremities. 

The  Lacteals. — All  along  the  intestines  are  little 
absorbent  tubes  known  as  lacteals.'^  These  unite 
in  little  groups  and  form  larger  tubes.  These  at 
last  all  terminate  in  a  single  tube,  about  the  size 

*  It  is  estimated  that  these  lacteals  number  about  seven  thousand 
in  each  square  inch  of  surface,  and  that  in  the  entire  length  of  the 
intestines  they  number  from  three  to  five  millions. 


42 


HOW   WE  LIVE. 


of  a  goose-quill,  which  lies  in  front  of  the  spinal 
column,  and  is  known  as  the  thoracic  duct. 


i-     f 

Fig.  7, — The  lacteals  and  their  connections  :  a,  portal  vein ;  3,  g,  thoracic 
duct ;  c,  groups  of  lacteals  ;  d^  e^  intestine  ;  /",  lacteals. 

The  greater  part  of  the  chyle  is  absorbed  by  the 
lacteals.     It  is  carried  to  the  thoracic  duct. 

Ascending  through  that  tube,  it  is  poured  into 
a  vein  which  lies  under  the  left  collar-bone,  or  clavi- 
cle, and  is  known  as  the  subclavian  vein.  It  now 
finds  its  way  to  the  heart  through  the  currents  from 
the  upper  extremities. 

Summary  of  Changes. — Food  is  masticated  in 
the  mouth  by  the  teeth,  and  is  mixed  with  saliva. 

The  aiHyiei^s  are  digested  by  the  action  of  the 
saliva,  the  pancreatic  juice,  and  the  intestinal  juices, 
and  by  a  change  effected  in  the  liver. 


HOW  DIGESTION  GOES  ON, 


43 


The  proteids  are  reduced,  or  dissolved,  in  the 
stomach  by  the  gastric  juice. 

Acids  are  neutralized  by  the  alkali  of  the  bile. 

Oily  substances  are  reduced  in  the  intestines  by 
the  action  of  the  bile  and  the  pancreatic  juice. 

These  several  changes  complete  digestion,  and 
change  food  so  that  it  readily  enters  the  blood. 

Hygiene  of  Digestion. 
Like  other  parts  of  the  body,  the  digestive  or- 
gans need  rest.  If  kept  constantly  in  action,  they 
become  weary  and  unable  to  perform  their  proper 
work.  From  this  fact,  and  from  the  lessons  which 
have  gone  before,  we  derive  the  following  hygienic 
laws  : 

I.  Take  food  that  can  be  digested. 

II.  The  food  should  be  so  prepared  as  to  digest 
most  easily. 

III.  Enough  food  should  be  taken  to  nourish 
the  body,  and  no  more."^ 

IV.  Food  should  be  taken  at  regular  times,  with 
intervals  between  sufficient  to  give  the  digestive 
organs  a  chance  to  rest.f 

*  The  best  guide  to  the  proper  kind  and  amount  of  food  is  a  health- 
ful appetite.  As  there  is  a  pleasure  in  eating,  however,  there  is  danger 
of  eating  too  much,  especially  if  the  food  is  taken  rapidly.  The  appe- 
tite, too,  may  be  spoiled  by  various  indulgences,  and  then  it  ceases  to 
be  a  guide.  In  such  cases  the  only  way  we  can  determine  what  is  best 
for  us  is  by  the  study  of  the  nature  of  foods,  and  by  experience  as  to 
what  seems  to  suit  our  own  conditions  best. 

f  If  children  must  eat  candy  and  sweetmeats,  the  best  time  for 
them  is  directly  after  a  meal,  as  the  habit  of  eating  between  meals  is 
very  injurious.  After  a  long  process  of  digestion,  the  tiny  digestive 
organs  become  tired,  and  it  is  wrong  to  overtax  them.     We  ourselven 


44  HOW   WE  LIVE. 

V.  At  meal-times,  and  until  digestion  in  the 
stomach  is  nearly  finished,  water  and  other  liquids 
should  be  taken  sparingly. 

VI.  Avoid  the  use  of  tobacco,  as  it  prevents  the 
changes  which  should  be  made  by  the  saliva. 

VII.  Avoid  the  use  of  alcoholic  drink,  because 
it  prevents  the  changes  which  should  be  made  by 
the  gastric  juice  and  by  the  liver. 

VIII.  Avoid  all  substances,  like  unripe  fruits, 
that  have  a  tendency  to  create  disturbances  in  the 
intestines. 

Something  to  Find  Out. 

1.  What  would  be  the  effect  if  the  serous  coat 
of  the  stomach  should  become  rough  ? 

2.  What  would  be  the  effect  if  the  muscular  coat 
should  cease  to  act  ? 

3.  What  effect  has  the  gastric  juice  upon  starch? 

4.  When  the  mouth  is  full  of  food,  should  we 
take  drink  to  ''  wash  it  down  "  ? 

5.  Why  is  it  better  to  take  drink  toward  the  end 
of  a  meal  than  at  the  beginning? 

6.  What  is  the  effect  of  taking  ice-cream  after  a 
meal? 

7.  How  do  vinegar  and  sour  fruit  sometimes 
improve  digestion  ? 

8.  Why  are  biscuits  containing  a  large  quantity 
of  soda  hurtful  ? 

9.  Under  what  circumstances  may  it  be  proper 
to  take  a  little  soda  into  the  stomach  ? 

need  a  rest  after  a  hard  task,  and  are  discouraged,  if,  when  our  work 
seems  to  be  done,  more  is  given  us  to  do.  So  it  is  with  the  little 
lacteals  and  absorbents.    It  is  not  fair  to  keep  them  constantly  at  work. 


HOW  DIGESTION  GOES  ON, 


45 


10.  Should    we   take    food    ''between    meals"? 
Why? 

11.  Should   we  eat  just  before   going  to  bed? 
Why? 

12.  What  is  the  harm  of  eating  when  we  are 
tired  ? 

13.  Should   we  engage  in  violent  exercise  just 
after  a  meal  ? 

14.  What  is  the  best  condition  to  be  in  for  the 
half-hour  before  and  after  meals  ? 

15.  What  are  the  best  foods  for  invalids  and  per- 
sons with  weak  stomachs  ? 

16.  What  is  the  general  difference   between  a 
proper  summer  and  winter  diet  ? 

17.  How  can  we  avoid  the  evil  effects  which 
tobacco  causes  in  the  stomach  ? 

18.  In  what  way  is  the  habit  of  taking  alcohoUc 
drinks  formed  ? 

19.  How  can  we  avoid  the  suffering  caused  by 
breaking  off  such  a  habit  ? 

20.  Why   do   people   begin   the   use   of   strong 
drink  ? 

21.  What  is  the  effect  of  eating  so  much  at  a 
meal  as  to  overload  the  stomach  ? 

22.  Mention  some  remedy  for  the  evil  of  over- 
eating. 

23.  What  is  better  than  medicine  to  preserve  a 
healthy  digestion  ? 


CHAPTER  IV. 

HOW  THE   BLOOD   GETS  PURIFIED 

The  newly  made  blood  brought  by  the  lacteals 
and  absorbents  is  poured  into  veins,  where  it  min- 
gles with  the  currents  returning  to  the  heart.  This 
blood  is  laden  with  materials  which  the  body  no 
longer  needs,  and  before  it  can  nurture  the  body  it 
must  be  purified.  For  this  purpose,  it  must  come 
in  contact  with  air,  to  which  it  may  give  off  the 
waste  matter  it  contains,  and  from  which  it  may 
receive  oxygen. 

The  Heart. 

On  its  way  to  the  air,  the  venous  blood  first  en- 
ters the  heart.  This  organ  is  placed  in  the  chest 
between  and  partly  behind  the  two  lungs,  and 
slightly  on  the  left  side.  It  is  about  as  large  as 
the  fist,  and  is  shaped  somewhat  like  a  pear.  It 
points  downward  toward  the  front.  It  is  made  up 
entirely  of  strong  muscular  fiber,  so  that  it  can  con- 
tract with  very  great  force.*     It  is  surrounded  by. 

*  It  has  been  found  that,  during  twenty -four  hours,  the  average 
healthy  human  heart  does  an  amount  of  work  equivalent  to  raising 
92.425  tons  one  foot  high,  or  of  raising  one  ton  over  92  feet  high.     A 


HOW   THE  BLOOD   GETS  PURIFIED, 


47 


a  smooth,  satin-like  membrane,  called  the  pericar- 
dium. 


Fig.  8.— The  heart  and  large  blood-vessels  :  A,  right  ventricle ;  B,  left  ven- 
tricle ;  C,  right  auricle  ;  Z>,  left  auricle  ;  E,  aorta  ;  F,  pulmonary  artery. 

The  Plan  of  the  Heart. — The  heart,  like  many 
other  parts  of  the  body,  has  a  double  structure. 

good  climber  can  only  raise  his  own  weight  9,000  feet  in  nine  hours, 
or  1,000  feet  an  hour  ;  while  the  work  done  by  the  heart  is  equivalent 
to  raising  its  own  weight  (ten  ounces)  13,860  feet  an  hour.  The  most 
powerful  engine  ever  made  by  man,  the  *'  Bavaria"  locomotive  of  the 
Vienna  and  Trieste  Railway,  can  only  raise  itself  through  2,700  feet  in 
an  hour ;  that  is,  its  energy  is  less  than  one  fifth  of  that  of  the  human 
heart. — ("  The  Heart  and  its  Function.") 


48  ^OIV   WE  LIVE. 

Its  right  and  left  sides  are  entirely  separated  b}? 
an  unbroken  wall  of  muscle.  In  structure,  the  two 
sides  are  nearly  alike,  but  each  side  has  its  own 
separate  work  to  do.  The  right  side,  which  re- 
ceives the  blood  from  the  veins  and  sends  it  to  the 
lungs  to  be  purified,  is  soitietimes  called  the  pulmo- 
nary heart ;  and  the  left  side,  which  receives  the 
blood  from  the  lungs  and  sends  it  out  to  nurture 
the  system,  is  called  the  systemic  heart. 

Each  side  of  the  heart  has  two  cavities,  the 
smaller  one  being  above,  and  the  larger  below. 
The  upper  cavities  are  called  auricles,  and  the  lower 
ones  ventricles.  As  the  blood  flows  from  the  veins 
into  the  auricles  gently,  the  walls  of  the  upper  part 
of  the  heart  are  not  so  thick  and  strong  as  if  they 
were  intended  to  sustain  a  heavy  strain. 

From  the  ventricles  the  blood  must  be  forced 
or  driven,  through  the  blood-vessels,  and,  in  conse- 
quence, the  muscular  walls  of  the  ventricles  are 
thick  and  strong. 

Between  the  auricles  and  ventricles  are  valves 
opening  downward,  which  admit  blood  freely  from 
above,  but  which  close  and  prevent  its  return.  The 
blood-vessel  leading  from  the  right  ventricle  to  the 
lungs  is  called  \\yq  pulmonary  artery. 

Pulmonary  Action. — The  currents  from  the  veins, 
one  from  the  upper  extremities  and  one  from  the 
lower,*  unite  and  empty  into  the  right  auricle  of 
the  heart.  The  walls  of  the  auricle  contract,  and 
force  the  blood  through  the  valve  into  the  right 

*  The  large  vein  from  above  is  called  the  superior  vena  cava  ;  and 
that  from  below,  the  inferior  vena  ca-va. 


HOW   THE  BLOOD  GETS  PURIFIED. 


49 


ventricle.  The  powerful  muscular  walls  of  the  ven- 
tricle then  contract,  the  valve  shuts,  and  the  blood 
is  driven  through  the  pulmonary  artery  to  the 
lungs,  where  it  comes  in  contact  with  the  air. 

The  Lungs. 
The  lujigs  are  in  two  divisions,  occupying  the 
right  and  left  sides  of  the  upper  part  of  the  chest. 


Fig.  9. —The  cavity  of  the  chest,  showing  the  positions  of  the  heart  and  the 
lun^  :  Ay  left  lung  ;  B,  heart ;  Z>,  pulmonary  artery  ;  E^  trachea,  or 
windpipe. 

The  right  side  has  three  distinct  parts  called  lobes^ 
the  left  has  two. 

Structure  of  the  Lungs. — The  lungs  are  made 


so 


HOW    WE  LIVE, 


up  of  soft,  elastic  tissue  arranged  in  the  form  of 
minute  cells.     These  cells  are  connected  with  small 


Fig.  io, — Air-passages  in  the  human  lungs :  ^,  larynx ;  *,  trachea ;  c,  d^ 
bronchi ;  <?,  bronchied  tubes  ;  y,  clusters  of  air<ells. 

passages,  which  open  into  larger  ones,  uniting  in  a 
single  pipe.  All  these  passages,  small  and  great, 
are  called  bronchial  tubes,  or  bronchi ;  and  the  pipe 
into  which  these  open  is  the  windpipe,  or  trachea. 
Lying  next  above  the  trachea  is  the  larynx,^  which 
opens  directly  into  the  throat,  and  through  the 
nasal  passages  and  the  mouth  into  the  air. 

The  pulmonary  artery  comes  out  of  the  right 
ventricle  of  the  heart  as  a  single  tube  ;  but  it  finally 
divides  into  five  branches,  one  extending  to  each  of 
the  five  lobes  of  the  lungs. 

Entering  the  lungs,  these  blood-vessels  divide 
into  minute  passages,  which  extend  to  every  part 

*  The  larynx  makes  a  lump  in  the  neck  which  we  can  feeL  and 
which  is  called  "  Adam's  apple." 


HOW   THE  BLOOD   GETS  PURIFIED.  51 

of  the  lungs,  and  surround  every  air-cell.  Indeed, 
the  lungs  may  be  considered  as  made  up  of  air- 
passages  and  blood-vessels,  with  just  enough  tissue 
to  form  the  necessary  cells  and  tubes."^  The  lungs 
are  surrounded  by  a  smooth  membrane  called  the 
pleura. 

How  the  Chest  Varies. — The  capacity  of  the 
chest  varies  with  the  breath,  increasing  as  the  breath 
comes  in,  and  diminishing  as  it  goes  out.  This 
change  is  effected  by  the  movement  of  the  ribs  and 
the  diaphragm.  In  the  process  of  breathing,  the 
respiratory  muscles  contract,  and  move  the  ribs  out- 
ward and  upward.  At  the  same  time,  by  the  con- 
traction of  the  muscles  of  the  diaphragm,  its  arch  is 
drawn  down,  and  the  cavity  of  the  chest  is  made 
both  broader  and  deeper. 

When  these  muscles  relax,  the  ribs  droop  down- 
ward, the  diaphragm  returns  to  its  arched  position, 
and  the  chest  is  narrowed  and  shortened. 

Forces  in  Breathing. — Breathing  is  brought 
about  by  two  forces — the  pressure  of  the  air,  and 
the  elastic  force  of  the  lung-tissue.  When  the  ribs 
are  elevated  and  the  diaphragm  is  depressed,  there 
is  a  tendency  to  produce  a  vacuum  between  the 
lungs  and  the  walls  of  the  chest.  The  air,  pressing 
fifteen  pounds  to  the  square  inch,  forces  its  way  into 
the  air-passages  of  the  lungs,  and  expands  the  lung- 
tissue  so  that  it  fills  the  enlarged  space  within  the 

*  If  two  small  trees  with  bushy  tops  were  placed  together  in  such  a 
way  that  the  branches  and  twigs  of  one  were  closely  interlaced  with 
the  branches  and  twigs  of  the  other,  they  would  show  how  the  divis- 
ions of  the  pulmonary  artery  and  those  of  the  air-passages  are  brought 
together  in  the  lungs. 


52 


HOW    WE  LIVE. 


chest.  This  act,  of  breathing  the  air  in,  is  called 
inspiration. 

When  the  ribs  and  the  diaphragm  return  to  their 
passive  condition,  as  the  tendency  to  a  vacuum  no 
longer  exists,  the  pressure  of  the  air  ceases,  and  the 
elastic  tissue  contracts,  forcing  the  air  out.  This 
act  of  breathing  out  is  called  expiration,  and  the 
whole  act  of  breathing  is  called  respiration. 

Action  in  the  Lungs. — At  every  inspiration  the 
air  passes  through  the  nose  *  or  the  mouth  into  the 
bronchials  and  finds  its  way  into  every  little  air-cell. 
The  walls  of  these  cells,  separating  them  from  the 
blood-vessels,  are  so  thin  that  air  and  gas  readily 
pass  through.  In  this  way  the  impure  matter  of 
the  blood  finds  its  way  into  the  air-cells,  and  the 
oxygen  of  the  air  enters  the  blood-vessels. 

Results  of  Breathing. — The  air,  which  comes 
into  the  lungs  pure,  goes  out  laden  with  carbonic- 
acid  gasf  and  other  impurities.  It  is  so  foul  that 
it  is  unfit  to  be  breathed  again. 

The  blood,  which  comes  into  the  lungs  laden 
with   impurities,  gives   off   waste   matter,  and   re- 

*  The  outer  nasal  passages  are  supplied  with  fine  hairs,  so  that  the 
air  on  its  way  to  the  lungs  is  filtered,  and  no  dust  is  allowed  to  pass. 
The  nose  has  also  the  sense  of  smell,  and  whenever  it  detects  foul 
odors  the  air  is  unfit  to  breathe.  The  nose  thus  becomes  a  sentinel  at 
the  gate  of  the  lungs.  For  these  reasons  we  should  always  breathe 
through  the  nose  instead  of  through  the  mouth. 

f  Carbonic-acid  gas  is  one  of  the  products  of  worn-out  animal  tissue. 
It  is  also  produced  by  burning  wood  and  coal,  and  in  other  ways.  Air 
that  contains  much  of  it  is  unfit  to  breathe.  It  is,  however,  one  of  the 
principal  supporters  of  vegetable  life.  Vegetation  takes  up  carbonic 
acid  and  pours  out  the  oxygen  necessary  to  animals.  The  two  great 
divisions  of  living  things  thus  continually  work  for  one  another. 


NO IV   THE  BLOOD  GETS  PURIFIED.  53 

ceives  life-giving  oxygen.  Its  color  is  changed 
from  a  dark,  dull  red  to  a  bright  scarlet,  and  it  is 
filled  with  the  strength  and  health  necessary  to 
nurture  the  body. 

Return  of  the  Blood. — The  blood,  thus  purified 
and  strengthened,  flows  from  the  small  passages 
of  the  pulmonary  artery  into  similar  small  passages 
of  the  pulmonary  veins.  These  small  vessels  open  into 
larger  ones,  and  finally  they  all  unite,  forming  four 
principal  tubes,  two  upon  the  right  side  and  two  upon 
the  left,  and  pour  the  blood  into  the  left  auricle  of 
the  heart.  The  blood  is  now  purified  and  ready  to 
be  sent  out  to  nourish  all  the  parts  of  the  body. 

Alcohol  in  the  Lungs. — The  alcohol  which  en- 
tered the  veins  from  the  liver  makes  its  appearance 
in  the  lungs.  As  it  does  not  become  a  part  of  the 
blood,  or  furnish  it  with  any  needed  element,  an 
effort  is  here  made  to  get  rid  of  it,  and  the  effect  is 
shown  in  the  peculiar  and  disagreeable  odor  of  the 
breath  of  habitual  drinkers. 

But  the  lungs  have  enough  to  do  to  relieve  the 
blood  of  its  waste  matter.  To  get  rid  of  the  alcohol 
requires  additional  work,  and  this  work,  when  ex- 
cessive and  continuous,  wearies  and  weakens.  After 
a  long  effort  in  trying  to  expel  alcohol,  the  lungs 
become  so  feeble  that  they  readily  contract  diseases 
such  as  pneumonia  and  consumption,  and  these  dis- 
eases are  much  more  rapid  and  violent  when  they 
take  hold  of  weakened  tissue. 

If  the  amount  of  alcohol  is  large,  the  lungs  can 
not  get  rid  of  the  whole  of  it,  and  a  portion  enters 
the  pulmonary  veins  and  mingles  with  the  currents 


54  HO  IV   WE  LIVE. 

that  circulate  through  the  body.  Here,  as  before 
the  alcohol  is  in  the  blood  but  not  a  part  of  it,  and 
efforts  are  made  to  expel  it  wherever  it  appears. 

Tobacco  in  the  Lungs. — In  smoking,  the  fumes 
of  tobacco  are  frequently  drawn  into  the  lungs. 
This  is  especially  the  case  in  smoking  cigarettes. 
The  effect  of  the  tobacco  upon  the  lung-tissue  is  to 
retard  its  action,  so  that  all  the  changes  effected  by 
breathing  are  more  slowly  performed.  In  this  way 
the  blood  goes  on  in  its  course  without  being  suffi- 
ciently purified,  and  is  therefore  unable  to  properly 
nourish  the  body.  The  first  result  is  a  feeling  of 
languor  and  repose,  and  this,  if  repeated,  often  be- 
comes torpor  and  stupidity. 

Tobacco  affects  children  most  unfavorably  be- 
fore they  have  attained  their  full  growth.  The  ac- 
tion of  the  organs  necessary  for  growth  and  bodily 
activity  is  retarded,  the  body  becomes  feeble,  and 
is  often  stunted.  The  mind  is  rendered  as  weak  as 
the  body,  and  many  times  it  loses  all  power  of  effect- 
ive study. 

The  Need  of  Pure  Air. — We  have  already  seen 
that  the  air  once  breathed  is  no  longer  pure.  It  is 
just  as  unfit  for  breathing  again  as  muddy  water  is 
for  drinking  or  decayed  food  for  eating.  But  air 
is  rendered  impure  in  many  other  ways.  From 
stagnant  water  and  from  decaying  animal  and  vege- 
table substances,  gases  arise  which  make  the  air  un- 
fit for  breathing.  Whenever  foul  air  is  breathed,  the 
blood  is  not  fully  purified,  and  the  body  is  not  prop- 
erly nourished.  Some  of  the  most  fatal  diseases  re- 
sult from  breathing  air  laden  with  foulness. 


HOH^    THE  BLOOD   GETS  PURIFIED.  55 

Hygiene  of  Respiration. 

As  air  is  a  necessity  of  life,  some  of  the  rules  that 
should  guide  us  in  regard  to  air  become  obvious : 

I.  When  the  nose  detects  an  unpleasant  odor, 
the  air  is  foul,  and  we  should  avoid  breathing  it,  if 
possible. 

II.  We  should  not  breathe  air  that  is  made  foul 
by  our  own  breath,  or  by  that  of  other  persons. 

III.  We  should  not  stay  long  in  a  crowded  room, 
unless  it  is  well  ventilated. 

IV.  We  ought  not  to  sleep  in  small,  ill-ventilated 
bedrooms. 

V.  Impurity  of  air  in  a  room  can  be  detected 
only  when  coming  in  from  fresh  air ;  hence  extra 
care  should  be  taken  to  thoroughly  ventilate  all 
occupied  rooms  every  day. 

VI.  We  ought  to  keep  away  from  the  vicinity 
of  stagnant  water. 

VII.  We  should  never  permit  decaying  animal 
or  vegetable  matter  to  remain  near  our  houses. 

VIII.  We  should  carefully  avoid  breathing  the 
gas  from  sewers,  sinks,  and  cess-pools. 

IX.  We  should  avoid  alcohol,  tobacco,  and  other 
articles  that  give  extra  foulness  to  the  breath. 

X.  No  article  of  dress  should  be  worn  so  tight 
as  to  prevent  the  expansion  of  the  chest  in  respira- 
tion. 

XL  The  weight  of  the  clothes  should  hang  from 
the  shoulders,  or  be  so  distributed  as  not  to  be  felt 
as  a  band  about  the  ribs. 

XII.  We  should  never  sit  or  stand  in  such  a  way 


56  HOW   IVE  LIVE. 

as  to  cramp  the  chest,  and  prevent  full  and  free  res- 
piration. 

Some  tiling  to  Fmd  Out. 

1.  What  parts  of  the  body  lie  next  to  the  heart? 

2.  Why  is  the  pericardium,  which  incloses  the 
heart,  smooth  on  the  outside  ? 

3.  What  besides  the  smooth  surface  of  this  mem- 
brane  prevents  friction  ? 

4.  What  kind  of   membrane  forms  the  pleura, 
and  what  is  its  use  ? 

5.  What  is  the  name  of  the  disease  to  which  the 
pleura  is  subject  ? 

6.  How  may  the  lungs  of  a  sheep  or  a  calf,  which 
we  get  from  a  butcher,  be  filled  with  air  ? 

7.  When  these   lungs   are  full,  how  is   the  air 
driven  out? 

8.  About  how  much  force  is  required  to  inflate 
our  lungs  ? 

9.  Why  is  it  more  difficult  to  breathe  on  the  top 
of  a  high  mountain  than  at  the  bottom  ? 

10.  Why  is  it  best  to  have  a  house  ''  somewhat 
back  from  a  village  street "  ? 

11.  Why  is  it  more  healthful  to  travel  after  a 
rain  than  before  ? 

12.  What  organ  serves  the  lungs  by  giving  warn- 
ing of  the  presence  of  foul  substances  ? 

13.  What  should  we  do  when  we  get  a  strong 
smell  of  carrion  ? 

14.  Why  should  we  not  take  a  pan  of  live  coals 
into  the  bedroom  which  we  occupy  ? 

15.  What  shall  we  do  when  we  detect  the  pres- 
ence of  carbonic-acid  gas  in  our  rooms  ? 


HOW  THE  BLOOD   GETS  PURIFIED.  57 

16.  In  what  way  does  foul  air  affect  the  pupils 
of  a  school  ? 

17.  How  should  the  cellar  of  a  house  be  kept? 

18.  What  kind  of  sink  in  a  kitchen  is  harmful? 

19.  What  should  be  done  with  apple  and  potato 
parings,  and  the  waste  part  of  vegetables  ? 

20.  What  is  to  be  done  with  tainted  meat  ? 

21.  Why  should  we  particularly  avoid  taking 
the  breath  of  persons  who  are  ill  ? 

22.  When  resting  after  violent  exercise,  what 
precaution  should  we  take  ? 

23.  Why  does  tobacco  affect  children  worse  than 
it  does  grown  people  ? 

24.  In  what  way  can  we  avoid  the  weakening 
effect  of  alcohol  on  the  lungs  ? 

25.  What  is  the  best  way  to  avoid  the  stupefying 
effect  of  tobacco  in  the  lungs  ? 

26.  In  building  a  school-house  or  a  dwelling- 
house,  why  should  we  place  it  at  a  distance  from  a 
swamp  ? 

27.  Why  will  a  person  coming  into  a  room  from 
the  out-door  air  detect  impure  air  in  a  room,  while 
the  inmates  are  unconscious  of  the  impurity  ? 

28.  In  building  halls,  churches,  and  places  of 
public  resort,  what  matter  needs  special  attention  ? 

29.  When  the  people  at  church  or  while  attend- 
ing a  lecture  become  sleepy,  what  is  probably  the 
matter  ? 

30.  As  the  cost  of  ventilating  a  single  school- 
room does  not  exceed  twenty  dollars,  what  excuse 
has  the  district  for  not  providing  means  of  ventila- 
tion? 


CHAPTER  V. 

HOW  THE  BLOOD  NURTURES  THE  BODY. 

Waste  and  Repair. — Every  time  we  take  a  step 
or  raise  an  arm,  portions  of  the  muscles  that  move 
are  used  up.  By  every  motion  some  part  of  the 
body  is  destroyed.  Each  action  of  the  stomach, 
each  heave  of  the  breath,  each  beat  of  the  heart, 
consumes  tissue ;  and,  indeed,  it  may  be  said  that 
every  part  of  the  body  is  all  the  time  wearing  out. 

But,  during  life,  nurture  also  is  always  going 
on.  Sharp  little  eyes  are  keeping  watch  over  every 
part  of  the  body,  and  nimble  little  fingers  are  busy 
in  repairing  and  restoring.  No  sooner  is  one  par- 
ticle removed,  than  another  takes  its  place.  On 
one  side  of  each  tiny  cell  the  invisible  sexton  is 
hurrying  away  matter  which  is  dead ;  on  the  other, 
the  unseen  builder  is  filling  the  vacant  space  with 
matter  which  is  living. 

From  birth  to  death  these  changes  are  going 
on.  The  agent  that  brings  them  about  is  the  blood. 
The  way  in  which  the  blood  sets  about  its  work  is 
by  circulation.  The  chief  cause  of  circulation  is 
the  action  of  the  heart. 

The  Arteries. — The  channels  leading  out  from 
the  heart  are  called  arteries.     They  are  made  of  a 


HOW   THE  BLOOD  NURTURES   THE  BODY. 


59 


Stiff,  elastic  material,  so  that  they  retain  their  shape 
when  pressed  upon,  and  regain  it  when  stretched 
or  bent.     Like  the  stomach,  they  have  three  coats. 

The  great  artery  leading  out  of  the  left  ventricle 
of  the  heart  is  the  aorta.  This  main  tube  divides, 
sending  large  branches  upward  to  the  head  and 
upper  extremities,  and  downward  to  the  lower  ex- 
tremities. These  branches  divide  again  and  again, 
until  they  terminate  in  minute  tubes  distributed  to 
every  part  of  the  body. 

The  Capillaries. — From-  the  extremities  of  the 
small  arteries  a  net-work  of  fine,  hair-like  tubes, 
called  capillaries,  extends  through  nearly  all  the 
tissues  of  the  body.  These  tubes  lie  so  close  to- 
gether that  we  can  scarcely  thrust  the  point  of  a 
fine  needle  into  any  part  of  the  body  without  pierc- 
ing some  of  them. 

The  Veins. — The  capillaries,  at  the  extremity 
opposite  to  the  arteries,  open  into  minute  veins. 
These  veins  come  together  and  form  larger  ones, 
until  they  all  unite  in  two  principal  channels — the 
superior  vena  cava  from  the  upper  extremities,  and 
the  inferior  vena  cava  from  the  lower.  These  two 
receive  the  blood  and  pour  it  into  the  right  auricle 
of  the  heart.  The  walls  of  the  veins  are  not  stiff, 
like  those  of  the  arteries,  but  readily  yield  to 
pressure. 

Action  in  the  Heart. — As  we  have  already  seen, 
the  purified  blood  from  the  pulmonary  veins  pours 
itself  into  the  left  auricle  of  the  heart.  The  muscu- 
lar walls  of  the  auricle  contract,  and  force  the  blood 
into  the  left  ventricle.     Then  the  walls  of  the  ven- 


6o  HOW   IVE  LIVE. 

tricle  contract,  the  valve  opening  from  the  auricle 
shuts,  and  the  blood  is  driven  through  the  arteries 
into  every  part  of  the  body.*  To  drive  the  blood 
so  far  and  so  rapidly  requires  a  great  amount  of 
force,  and  therefore  the  walls  of  the  left  ventricle 
of  the  heart  are  very  thick  and  strong. 

Action  in  the  Arteries. — The  arteries  are  usu- 
ally placed  deep  in  the  flesh,  to  be  out  of  the  way 
of  harm.  The  blood  is  forced  into  them  by  jets  at 
each  heart-beat.  Their  elastic  walls  yield  to  the 
rush,  but  contract  again,  helping  the  blood  along 
its  course.f  In  this  way  the  minute  vessels  are 
filled,  and  the  beating  or  pulsation  which  began  at 
the  heart  is  carried  on  to  the  extremities,  so  that 
every  part  of  the  body  is  quivering  with  motion 
and  life. 

Action  in  the  Capillaries. — From  the  extremis 
ties  of  the  small  arteries  the  blood  enters  the  capil- 
laries. In  each  the  stream  is  very  minute  and  flows 
at  an  even  rate.  Here  nutrition  takes  place.  Oxy- 
gen from  the  blood  unites  with  particles  of  tissue, 

*  The  average  number  of  heart-beats  in  a  minute  is  about  seventy. 
The  number  is  greater  in  children  than  in  adults,  and  greater  in  women 
than  in  men.  With  the  body  in  a  standing  position,  the  heart  has  not 
only  to  force  the  blood  to  all  parts  of  the  body,  but  has  to  lift  it  from 
the  chest  to  the  head,  and  from  the  feet  to  the  chest.  When  we  lie 
down,  the  heart  is  relieved  from  this  necessity  of  lifting,  and  its  ac- 
tion is  diminished.  The  amount  of  blood  which  the  heart  moves  is 
estimated  at  eighteen  pounds  per  minute. 

f  At  the  wrist,  and  at  some  other  parts  of  the  body  where  the  ar- 
teries come  near  the  surface,  we  can  feel  the  pulse.  Each  beat  of  the 
pulse  is  the  yielding  of  the  artery  to  a  beat  of  the  heart.  One  of  the 
surest  means  by  which  the  physician  finds  out  the  condition  of  the  body 
is  the  beating  of  the  pulse. 


ffOlV   THE  BLOOD  NURTURES   THE  BODY.     6 1 

and  burns  them,  causing  both  the  heat  and  the  mo- 
tion of  the  body.  The  particles  thus  destroyed  by 
use  are  taken  up  and  carried  away,  and  new  par- 
ticles full  of  life  and  strength  are  deposited  in  their 
place.  In  this  way  tissue  is  repaired,  vigor  is  re- 
stored, health  is  kept  up,  and  life  is  continued. 

Action  in  the  Veins. — The  blood  as  it  enters 
the  veins  from  the  capillaries  is  changed.  The 
limpid  current  has  become  thick  and  turbid  ;  the 
bright  scarlet  has  deepened  to  a  dark,  dull  red. 
The  jets  have  ceased,  and  the  current  flows  on 
smoothly  and  evenly.  All  along  the  courses  of  the 
veins,  valves  open  toward  the  heart,  so  as  to  allow 
the  blood  to  freely  flow  in  that  direction  ;  but  they 
shut,  so  as  to  prevent  its  return.  In  action,  the 
muscles  press  upon  the  veins  and  hasten  the  flow  ; 
so  that  work,  play,  and  exercise  of  every  kind,  help 
the  blood  along  its  course.*  From  the  veins  the 
blood  flows,  as  we  have  seen,  into  the  right  auricle 
of  the  heart. 

Alcohol  in  the  Blood. — The  alcohol  which  the 
lungs  can  not  expel  returns  to  the  heart  and  enters 
the  general  circulation.  Although  never  becoming 
a  part  of  the  blood,  its  power  for  mischief  continues. 
It  causes  blood-particles  to  shrink,  probably  by  ab- 

*  Persons  who  are  obliged  to  stand  much  of  the  time  are  often 
troubled  with  what  are  called  varicose  veins.  The  forces  that  cause 
circulation  are  not  sufficient  to  raise  the  blood  from  the  feet  to  the 
heart  through  so  many  hours  without  rest ;  and  in  consequence  the 
blood  presses  back  on  the  veins  until  they  yield  to  the  pressure  and 
gradually  enlarge.  The  valves  soon  become  useless,  increasing  the 
pressure  and  the  enlargement.  The  only  remedy  is  a  change  to  some 
employment  that  will  require  less  standing. 


62  HOW    WE  LIVE. 

sorbing  moisture  from  them,  so  that  they  can  not 
take  up  the  proper  amount  of  oxygen  in  the  lungs. 
As  a  result,  incomplete  combustion  takes  place  in 
the  capillaries  ;  the  veins  receive  half-burned  parti- 
cles which  the  lungs  can  not  expel ;  dead  matter  en- 
ters the  arteries,  vitiating  the  blood  ;  and  the  repair 
of  waste  is  interrupted  or  imperfectly  performed. 

The  continual  use  of  alcohol  also  often  changes 
the  muscular  tissue  of  the  walls  of  the  heart  into  a 
fatty  substance  which  can  not  bear  the  strain  put 
upon  it.  In  consequence,  when  a  person  gets  in 
this  condition  he  has  no  strength  to  move  about, 
and  often  he  can  not  stand.  Sometimes  the  weak- 
ened walls  burst,  causing  instant  death. 

The  constant  presence  of  alcohol  is  also  felt  in 
the  arteries.  It  causes  an  enlargement  of  the  minute 
vessels,  so  that  blood  accumulates  in  them  and  inter- 
rupts the  usual  flow  through  the  body.  This  is 
shown  by  the  flushed  face  of  a  person  who  has  been 
drinking.  The  effect  of  a  single  drink  will  soon  pass 
away,  and  the  arteries  will  regain  their  form  ;  but 
the  red  faces  and  redder  noses  of  those  who  drink 
to  excess  show  that  these  vessels  may  become  per- 
manently enlarged. 

Hygiene  of  the  Circulation. 

I.  We  should  breathe  pure  air,  and  frequently 
take  long,  deep  breaths,  so  that  the  blood  may  be 
properly  purified. 

II.  We  should  not  take  into  our  stomachs  any- 
thing that  enters  the  blood  but  does  not  become  a 
part  of  it. 


NOU^   THE  BLOOD  NURTURES   THE  BODY.     63 

III.  We  should  avoid  the  use  of  anything  that 
disturbs  the  regular  action  of  the  heart  and  prevents 
the  full  nutrition  of  the  body. 

IV.  We  should  relieve  the  heart  of  much  hard 
labor  by  taking  regular  and  sufficient  exercise. 

V.  Should  the  heart  show  signs  of  weakness,  we 
may  favor  its  recovery  by  taking  a  reclining  posi- 
tion. 

VI.  We  may  also  greatly  assist  circulation,  and 
so  relieve  the  heart,  by  daily  rubbing  the  skin 
briskly  with  a  brush  or  a  coarse  towel. 

VII.  We  should  avoid  the  use  of  all  substances 
that  tend  to  enlarge  small  blood-vessels  and  give  a 
permanent  redness  to  the  face. 

Something  to  Find  Out. 

1.  When,  and  by  whom,  was  the  circulation  of 
the  blood  first  discovered  } 

2.  How  much  blood  does  the  heart  move  in  an 
hour  ?  in  a  day  ?  in  a  year  ? 

3.  If  half  the  blood  flows  to  the  upper  extremi- 
ties, an  average  of  one  foot  above  the  heart,  one 
pound  of  blood  is  raised  how  many  feet  in  a  min- 
ute ?  how  many  in  an  hour  ? 

4.  How  can  we  tell  the  difference  between  a  vein 
and  an  artery  that  is  near  the  surface  ? 

5.  Which  way  does  the  blood  flow  in  the  arter- 
ies ?  in  the  veins  ? 

6.  When  a  blood-vessel  is  ruptured,  how  can  we 
tell  whether  it  is  an  artery  or  a  vein  ? 

7.  If  a  vein  is  wounded  in  one  of  our  limbs,  how 
may  the  flow  of  blood  be  stopped  ? 


64  ffOW   WE  LIVE. 

8.  On  which  side  of  the  wound  should  the  band 
be  placed  ? 

9.  In  case  an  artery  is  wounded,  where  should 
the  band  be  placed  ?     Why  ? 

10.  When  an  accident  occurs,  and  blood  is  flow- 
ing freely,  what  should  we  use  as  a  band  ? 

11.  How  can  we  draw  the  band  tight  enough  to 
stop  the  flow  of  blood  ? 

12.  If  the  wound  is  on  the  head,  neck,  or  trunk, 
what  is  to  be  done  ? 

13.  In  case  of  serious  wounds,  what  next  is  to  be 
done  after  stopping  the  flow  of  blood  ? 

14.  When  blood  flows  from  the  veins,  what 
change  in  it  takes  place  from  exposure  to  the  air  ? 

15.  How  does  this  change  affect  the  flow  of  the 
blood  from  small  veins  ? 

16.  What  forces  besides  the  heart-beat  assist  in 
the  circulation  of  the  blood  ? 

17.  How  does  a  reclining  position  relieve  the 
heart  ? 

18.  In  its  effect  upon  circulation,  how  does  the 
work  of  a  farmer  compare  with  that  of  a  clergy- 
man? 

19.  How  does  the  work  of  a  cook  compare  with 
that  of  a  sewing-girl  in  its  effect  upon  the  heart  ? 

20.  How  may  a  person  whose  business  confines 
him  to  a  sitting  posture  relieve  his  heart  of  extra 
work,  and  so  preserve  his  health  ? 

21.  Why  should  clerks  in  stores  be  permitted  to 
sit  a  portion  of  the  time  ? 

22.  In  regard  to  circulation,  to  what  particular 
danger  are  conductors  on  railroads  exposed  ? 


HOW   THE  BLOOD  NURTURES   THE  BODY.     65 

23.  When  attending  school,  what  should  we  do 
to  promote  circulation  ? 

24.  Why  is  exercise  out-of-doors  usually  better 
for  the  health  than  exercise  in  the  school-room  ? 

25.  If  a  person  is  found  exhausted,  with  his  skin 
pale  and  cold,  what  is  the  trouble  as  regards  circu- 
lation?    What  is  the  remedy? 

26.  When  a  sudden  chill  drives  the  blood  away 
from  the  surface,  what  should  be  done  at  once  ? 

27.  What  are  some  of  the  common  causes  of 
chills? 

28.  What  are  some  of  the  ways  of  stopping  per- 
sistent bleeding  at  the  nose  ? 

29.  When  persons  faint,  in  what  position  should 
they  be  placed,  and  what  remedies  should  be  ap- 
plied ? 

30.  In  what  way  can  we  avoid  the  red  blotches 
on  the  skin  which  come  from  the  use  of '*  strong 
drink"? 


CHAPTER  VI. 

HOW  THE  BODY  IS  ABLE  TO  MOVE. 

Motion  necessary  to  Life. — In  finding  out  how 
the  body  is  nourished,  we  have  seen  that  motions 
are  required.  To  get  and  prepare  the  food  which 
the  body  needs,  we  must  make  many  movements 
of  the  arms,  the  legs,  and  various  other  parts  of  the 
body.  To  chew  the  food,  we  must  move  the  jaws. 
The  rings  of  the  esophagus  must  successively  con- 
tract, in  order  to  force  the  food  into  the  stomach. 
The  stomach  must  keep  up  a  vigorous  action,  in 
order  to  churn  its  contents  into  chyme.  The  heart 
must  keep  on  contracting  and  expanding,  in  order 
to  send  the  blood  through  the  arteries  to  the  va- 
rious parts  of  the  system.  The  movements  by 
which  breathing  is  carried  on  must  never  cease. 
The  head  must  move  in  various  directions,  in  order 
to  pay  attention  to  what  is  going  on  about  it.  In 
fact,  the  parts  of  the  body  are  always  in  motion. 
Besides  the  motions  which  we  notice,  there  are  al- 
ways going  on  within  us  many  movements  which 
we  do  not  notice,  but  which  are  necessary  to  our 
existence  ;  and,  when  we  can  no  longer  discover 
any  motion  in  the  body,  we  know  that  it  is  dead. 


HOW   THE  BODY  IS  ABLE   TO  MOVE.       6/ 

The  Muscles. 

In  order  to  produce  all  these  motions,  it  is  plain 
that  the  body  must  be  provided  with  proper  appa- 
ratus ;  and,  on  examination,  we  find  that  the  greater 
part  of  what  we  call  flesh  is  collected  into  bands, 
and  so  fastened  to  the  various  parts  of  the  body  as 
to  pull  them  in  the  different  directions  required. 
These  fleshy  bands  are  called  muscles.  They  are 
about  five  hundred  in  number,  and  have  many  dif- 
ferent sizes,  shapes,  and  lengths,  according  to  the 
work  they  have  to  do.  Besides  their  use  in  pro- 
ducing bodily  motion,  in  which  they  may  be  com- 
pared to  the  ropes  of  a  ship,  they  are  so  arranged 
as  to  give  beauty  and  symmetry  to  the  form.* 

General  Structure  of  Muscles. — The  steak  which 
we  eat  for  breakfast,  and  all  the  other  lean  meat 
which  we  have,  is  muscle.  When  we  examine  such 
a  piece  of  meat  especially  after  it  has  been  boiled, 
we  find  that  it  is  made  up  of  fibers,  all  extending 
in  the  same  direction,  and  bound  together  by  a  thin 
membrane  called  connective  tissue.  When  the  fibers 
are  placed  under  a  microscope,  they  are  seen  to  be 
composed  of  a  collection  of  still  finer  strands,  or 
threads,  called  jibrils.\  Some  of  the  muscles  are 
round,  some  are  flat ;  some  are  not  more  than  a 
sixth  of  an  inch  long,  while  others  are  more  than 

*  The  plumpness  of  the  body  is  still  further  increased  by  the  layers 
of  fat  with  which  the  muscles  are  surrounded. 

f  In  the  muscles  which  are  controlled  by  the  will,  the  fibers  are 
crossed  by  regular  lines,  or  stripes.  There  are  about  ten  thousand  of 
these  lines  to  an  inch,  and  the  muscles  in  which  they  appear  are  said 
to  be  striped,  or  striated. 

5 


68 


HOW   WE  LIVE. 


two  feet  in  length.      Most  of  them  have  a  large 
body,  or  swell,  in  the  middle,  and  gradually  grow 

smaller  toward  the  ends ;  but  a  few 

are  small  in  the  middle  and  large  at 
the  ends. 

Tendons. — Some  of  the  muscles 
are  joined  directly  to  the  bones  upon 
which  they  act ;  but  most  of  them  be- 
come smaller  and  tougher  toward  the 
ends,  and  at  last  terminate  in  strong, 
bluish -white  cords,  called  tendons. 
The  tendons  are  directly  attached  to 
the  bones.  They  have  no  power  of 
contraction.  Wherever  the  tendons 
or  muscles  have  a  tendency  to  pull 
away  from  their  positions,  as  at  the 
wrist  and  the  ankle,  they  are  bound 
in  place  by  stout  bands,  called  liga^ 
ments. 

Hollow   Muscles.  —  Some   of   the 
muscles  are  not  intended  to  connect 
one  part  with  another,  but  form  ves- 
FiG.ii.-Themus-  g^^g  ^^  contain  fluids.     Such  are  the 

cles  and  tendons  i    i  •  i  n  i 

of  the  lower  arm,   heart  and  the  middle  or  muscular  coat 
showing  also  the  q{  ^^e  stomach,  which  have  already 
been  described. "^ 

How  the  Muscles  Act.— All  the 
muscles  have  power  to  contract  or  become  shorter ; 
and,  when   the   exciting  cause  is  removed,  to   re- 

*  The  muscular  fibers  of  the  blood-vessels,  of  the  lymphatic  vessels, 
of  the  alimentary  canal,  of  the  ducts  of  the  glands,  and  of  the  iris  of 
the  eye,  are  so  arranged  as  to  form  hollow  muscles. 


•igament  encir- 
cling the  wrist. 


HOW   THE  BODY  IS  ABLE   TO  MOVE.        69 


turn  to  their  ordinary  forms.  Those  whose  con- 
traction is  under  the  control  of  the  will  are  called 
voluntary  muscles.  Such  are  those  by  which  the 
motions  of  the  limbs  are  produced.  Those  which 
contract  without  any  conscious  action  of  the  mind, 
as  the  heart  and  the  stomach,  are  called  involun- 
tary muscles.  Some,  like  those  which  enable  us 
to  breathe,  usually  act  of  their  own  accord,  but 
may  to  a  certain  extent  be  influenced  by  the  will. 
Many  of  the  muscles  are  arranged  in  pairs,  one 
causing  motion  in  a  certain  direction,  and  the 
other  causing  mo- 
tion in  the  oppo- 
site direction. 

The  muscles 
that  bend  a  joint 
to  move  any  part 
are  called  flexors  ; 
those  that  extend 
the  parts  again  are 
called  extensors. 

For  example, 
when  we  bend  the 

arm  at  the  elbow,  the  large  muscle  in  the  front  of 
the  upper  part  of  the  arm  contracts  ;  and  when 
we  straighten  the  arm  again,  the  muscle  on  the 
opposite  side  of  the  arm  contracts.  When  there 
is  a  great  variety  of  motions  in  a  single  joint,  or  in 
any  organ,  each  distinct  movement  requires  a  sepa- 
rate muscle.  The  swing  of  the  arm  at  the  shoulder, 
the  roll  of  the  eye,  the  twisting  of  the  wrist  and  of 
the  ankle,  are  examples  of  this  arrangement.    The 


Fig.  12. 


The  left  arm,  showing  the  muscles  in 
action. 


70 


HOW    IVE  LIVE. 


contraction  of  muscles  attached  to  bones  gives 
motion  to  the  limbs,  the  trunk,  and  the  head.  The 
action   of   the   hollow  muscles   gives  the   motions 

necessary  for  the 
functions  of  the  in- 
ternal organs  and 
for  the  circulation 
of  the  blood. 

How  the  Mus- 
cles gain  Strength. 
—  We  have  al- 
ready seen  how 
the  blood  carries 
off  the  worn-out 
tissues  of  the 
body,  and  leaves 
in  their  place  new 
material  to  repair 
the  waste.  The 
muscles  are  thus 
nourished  by  the  food  in  the  same  manner  as  the 
other  parts  of  the  body.  But  Nature  has  also 
provided  that  those  parts  of  the  body  which  work 
the  hardest  shall  have  the  most  help  and  the  most 
abundant  nourishment.  So,  whenever  a  muscle  is 
used  a  great  deal,  the  blood  carries  to  it  an  unusual 
amount  of  material  to  make  and  to  keep  it  strong. 
It  therefore  happens  that  those  muscles  which  are 
used  most  become  largest  and  strongest.* 

*  The  arm  of  a  blacksmith  is  used  so  much  and  so  vigorously  that 
its  muscles  become,  not  only  much  larger  than  those  of  an  ordinary 
person,  but  also  much  harder.     The  same  is  true  of  those  who  practice 


Fig.  13. 


-The  muscles  of  the  legs,  as  in  the  act 
of  walking. 


HOW   THE  BODY  IS  ABLE   TO  MOVE.        yi 

The  Muscles  need  Rest. — So  long  as  the  mus- 
cles are  in  motion  they  are  wearing  out.  To  give 
time  and  opportunity  for  the  repairs  which  are 
needed  and  which  Nature  desires  to  make,  the  mo- 
tion of  the  muscles  must  cease  from  time  to  time. 
After  we  have  used  any  muscle  a  proper  length 
of  time,  it  becomes  tired.  This  is  Nature's  signal 
that  it  has  done  enough,  and  needs  to  be  repaired. 
When  a  muscle  is  thus  weakened  and  Nature  has 
given  the  signal  for  rest,  it  is  just  as  unwise  to  use 
it  as  it  is  to  use  a  bridge  which  has  been  pro- 
nounced unsafe,  or  a  rope  with  broken  strands.  Its 
use  may  perhaps  continue  for  a  time  without  seri- 
ous consequences,  but  it  may  result  in  permanent 
injury  of  the  weakened  part,  and  possibly  the  death 
of  the  offender. 

"  Exercise  for  Health,  not  for  Strength." — As 
there  are  in  the  world  enough  useful  things  to  do, 
it  is  best  to  fit  ourselves  to  do  them,  instead  of  fit- 
ting ourselves  to  perform  useless  feats  of  strength. 
It  is  the  duty  of  every  person  to  be  as  healthy  as 
possible,  and  to  so  train  the  body  that  it  can  carry 
out  the  directions  of  the  mind.  Therefore,  any 
kind  or  amount  of  exercise  that  will  keep  the  whole 
body  fresh  and  vigorous  is  desirable  ;  but  any  kind 
or  amount  of  training  that  is  designed  to  develop 
one  part  of  the  body  at  the  expense  of  the  rest,  sole- 
ly for  the  purpose  of  display,  should  be  discouraged. 
The  amount  of  vitality  at  our  disposal,  and  our  ca- 
pacity for  work,  may  probably  be  increased  by  judi- 

fowing,  or  who  engage  in  any  business  requiring  unusual  muscular 
effort. 


72  HOW    WE  LIVE. 

cious  exercise  ;  but  there  seems  to  be  a  limit  to  this 
increase.  If  we  perform  exhaustive  bodily  labor, 
the  mind  can  not  have  so  large  a  share  of  our  vital- 
ity as  would  otherwise  be  the  case.  On  the  other 
hand,  long  and  vigorous  action  of  the  mind  exhausts 
so  much  of  our  vital  power  that  the  body  can  not 
be  so  active. 

This  inclination  of  Nature  to  give  the  most  help 
to  the  part  that  is  working  hardest  or  has  the  most 
to  do,  is  the  reason  why  we  should  not  try  to  do 
any  bodily  or  mental  work  immediately  after  a 
hearty  meal,  as  the  vital  powers  are  then  needed  in 
the  processes  of  digestion.  For  the  same  reason  we 
should  not  eat  more  than  we  need  ;  for,  if  we  do,  so 
much  vitality  will  be  spent  in  digestion  that  we  can 
not  do  the  bodily  or  mental  work  of  which  we  would 
otherwise  be  capable. 

Hygiene  of  the  Muscles. 

I.  We  should  eat  plenty  of  wholesome  food,  in 
order  that  the  muscles  may  grow. 

II.  We  should  exercise  all  the  muscles  of  the 
body,  so  that  they  may  become  strong  and  healthy. 

III.  We  should  exercise  all  the  muscles  frequent- 
ly, to  quicken  the  flow  of  blood  in  the  veins,  so  as 
to  take  off  some  of  the  strain  from  the  heart. 

IV.  We  should  not  exercise  to  such  an  extent 
that  all  the  vital  forces  of  the  body  are  used  up  in 
muscular  action. 

V.  Any  kind  of  exercise  may  become  more  in- 
jurious than  useful,  if  it  is  allowed  to  overstep  the 
bounds  of  moderation. 


HOW   THE  BODY  IS  ABLE   TO  MOVE. 


73 


VI.  After  each  period  of  activity,  the  muscles 
need  rest — daily  rest  after  daily  toil,  and  a  long 
period  of  rest  after  the  exhaustive  strain  of  long- 
continued  work. 

VI I.  We  should   carefully   avoid   all   habits  of 


Fig,  14.— Improper  and  proper  positions  in  sitting. 

posture,  movement,  or  dress  that  will  interfere  with 
the  free  development  and  action  of  all  the  mus- 
cles. 

VIII.  In  sitting,  we  should  always  keep  the 
body,  as  nearly  erect  as  we  can  without  special  in- 
convenience.^ 

IX.  All  the  movements  of  the  body  should  be 

*  We  can  accustom  ourselves  to  sitting  erect  by  always  being  care- 
ful to  sit  well  back  on  a  chair,  and  not  upon  its  edge,  as  the  latter 
position  distorts  the  spine  and  produces  round  shoulders. 


74 


HOW   WE  LIVE. 


as  graceful  as  possible,  in  order  that  they  may  be 
agreeable  to  others. 

X.  Calisthenics  and  gymnastics  are  well  adapted 
to  give  grace  to  the  movements  of  the  body,  and 
also  furnish  excellent  exercise  for  young  persons. 
They  should,  therefore,  be  generally  used  in  schools. 

XI.  With  all  their  other  exercise,  children  need 


Fig.  15. — Proper  and  improper  positions  in  standing  :  i,  a  vertical 
line  ;  2,  the  spinal  column. 

plenty  of  active  play  to  keep  their  muscles  in  a 
healthful  condition. 

XII.  All  kinds  of  athletic  sports  and  manly  ex- 


HOIV   THE  BODY  IS  ABLE   TO  MOVE.        75 

ercises  that  are  not  actually  dangerous  should  form 
a  part  of  every  boy's  education. 

XIII.  Lawn -tennis,  croquet,  horseback  -  riding, 
or  similar  exercises,  should  form  a  part  of  the  life 
of  every  girl  who  is  not  otherwise  provided  with 
active  physical  employment. 

XIV.  When  work  distorts  the  body  by  giving 
excessive  exercise  to  the  muscles  that  throw  the 
shoulders  forward,  we  should  remedy  the  evil  by 
purposely  exercising  the  muscles  that  draw  the 
shoulders  back. 

XV.  We  should  avoid  the  habitual  use  of  beer, 
because  it  has  a  tendency  to  turn  healthy  muscle 
into  a  kind  of  spongy  fat. 

XVI.  When  in  health,  we  should  avoid  the  use 
of  all  stimulants  and  narcotics,  as  they  tend  directly 
to  weaken  the  muscles  and  to  diminish  muscular 
action. 

Something  to  Fmd  Out. 

1.  Why  are  the  muscles  of  the  right  arm  usually 
larger  than  those  of  the  left  ? 

2.  Why  are  so  many  men,  who  work  hard,  round- 
shouldered  ? 

3.  In  what  way  can  the  tendency  to  become 
round-shouldered  be  prevented  ? 

4.  What  good  comes  from  the  practice  of  the 
game  of  base-ball  ?  What  caution  needs  to  be  ob- 
served ? 

5.  What  is  the  effect  of  a  tight  band  around  a 
muscle  ? 

6.  When  the  fist  is  clinched,  where  do  the  mus- 
cles contract  and  become  rigid  ? 


76  NO  IV   WE  LIVE. 

7.  Does  the  expansion  as  well  as  the  contraction 
of  a  muscle  upon  one  of  the  limbs  produce  motion  ? 

8.  Why  is  better  exercise  obtained  by  rowing 
than  by  walking  ? 

9.  Why  is  it  wrong  to  keep  children  still  for  a 
long  period  at  a  time  ? 

10.  When  children  are  restless  in  school^  what 
are  some  of  the  probable  causes  ? 

11.  What  are  some  of  the  advantages  to  be 
gained  by  "  going  a-fishing  "  ? 

12.  What  is  the  best  time  for  muscular  rest  ? 

13.  Will  it  tire  a  horse  more  to  travel  on  a  level 
road,  or  on  a  moderately  hilly  one  ? 

14.  Why  can  not  the  arm  hold  out  a  weight  for 
a  long  time  ? 

15.  Why  should  we  not  engage  in  active  muscu- 
lar exercise  just  before  eating  ? 

16.  After  a  period  of  hard  study,  what  kind  of 
exercise  should  be  taken  ? 

17.  In  running,  or  other  violent  exercise,  what 
peculiar  symptom  tells  us  when  to  stop  ? 

18.  What  is  the  consequence,  if  we  do  not  obey 
the  command  ? 

19.  What  is  the  best  employment  for  the  half- 
hour  before  going  to  bed  ? 

20.  When  a  boy  or  a  girl  is  not  really  ill,  what 
do  stooped  shoulders  and  a  shuffling  gait  indicate  ? 

21.  Why  does  going  half  a  mile  on  an  errand 
sometimes  tire  a  boy  more  than  walking  five  miles 
to  see  a  circus  ? 

22.  If  a  person  is  free  to  choose  his  work,  what 
principle  should  guide  his  choice  ? 


CHAPTER  VII. 

HOW  THE  BODY  IS  ABLE  TO  STAND. 

The  Need  of  a  Bodily  Frame. — If  the  body  were 
made  up  entirely  of  soft  materials  like  the  muscles, 
it  might  be  capable  of  motion  in  its  different  parts 
and  some  movement  as  a  whole.  But  it  would  not 
be  able  to  stand  erect,  or  to  retain  any  permanent 
shape.  Its  beautiful  proportions,  its  graceful  mo- 
tions, and  its  dignified  bearing  would  all  be  impos- 
sible ;  and  a  human  being  would  be  nothing  more 
than  a  mass  of  flesh  physically  inferior  to  almost 
every  other  animal  in  existence.  That  it  may  be 
able  to  stand  erect  and  keep  its  proper  form,  the 
body  needs  a  strong  and  solid  frame-work.  This  is 
furnished  by  the  bones. 

The  Bones. 

Uses  of  the  Bones. — The  bones  have  three  dis- 
tinct uses.  They  give  shape  to  the  body,  and  keep 
the  various  parts  and  organs  in  position.  They  pro- 
tect organs  which  would  otherwise  be  exposed  to 
injury.  They  afford  a  solid  place  for  the  attach- 
ment of  muscles  by  means  of  which  motion  may  be 
given  to  the  various  parts  of  the  body. 


78  HOW   WE  LIVE. 

Forms  of  Bones. — In  order  to  meet  these  re- 
quirements, the  bones  have  many  different  sizes  and 
shapes,  and  are  arranged  in  the  various  ways  best 
suited  to  the  purposes  for  which  they  are  designed. 
Those  whose  chief  use  is  to  protect  are  made  strong 
and  thick,  and  of  such  shape  as  to  offer  most  resist- 
ance with  the  least  material.  Where  several  bones 
unite  to  protect  any  organ,  they  are  placed  around 
it  in  such  a  manner  as  will  defend  it  most  effectually. 
Those  whose  chief  use  is  to  furnish  support  to  the 
body,  or  a  base  of  attachment  for  other  portions,  are 
very  thick  and  solid,  and  of  such  shape  as  will  best 
adapt  them  for  staying  in  place.  Those  designed 
to  strengthen  columns,  or  to  produce  motion,  are 
long  and  straight.  Others,  which  have  more  than 
one  of  these  functions  to  perform,  are  so  ingenious- 
ly constructed  that  they  combine  two  or  more  of 
these  features. 

Structure  of  the  Bones. — The  long  bones,  which 
form  the  frame-work  of  the  limbs,  consist  of  a  slen- 
der shaft  of  hard,  compact  material,  and  have  en- 
larged extremities  composed  of  a  soft,  spongy  ma- 
terial.^ The  shaft  is  hollow  in  the  middle,  and 
contains  marrow.  This  is  composed  chiefly  of  blood- 
vessels and  fat,  and  supplies  the  bone  with  nourish- 
ment. The  other  bones  are  spongy  inside,  and  hard 
and  fine  in  texture  on  the  outside.f     The  bones  are 

*  The  increased  size  and  the  spongy  character  of  the  extremities 
furnish  better  attachments  for  the  tendons,  and  the  increase  in  size 
makes  up  for  the  decrease  in  hardness. 

f  The  bones  are  full  of  fine  tubes  from  ^-otj  to  jiroTnr  of  ^^  i^^ch  in 
diameter.  Through  these  the  blood  passes  to  carry  on  the  work  of 
repair,  as  in  the  other  portions  of  the  body. 


HOW  THE  BODY  IS  ABLE   TO  STAND. 


79 


covered  with  a  tough,  fibrous  membrane,  except  at 
the  joints,  where  they  are  covered  with  cartilage. 
This  fibrous  membrane  is  called 
the  periosteum,  and  when  it  is 
removed  the  bone  dies. 

Materials  of  which  the  Bones 
are  Made. — When  a  bone  has 
been  burned  for  a  sufficient 
length  of  time  it  will  be  so  brit- 
tle that  it  can  be  easily  broken. 
If  it  be  soaked  in  diluted  muri- 
atic acid  it  will  entirely  lose  its 
stiffness,  and,  if  of  sufficient 
length,  can  be  tied  in  a  knot. 
By  these  experiments  it  will  be 
seen  that  the  bones  contain  a 
mineral  or  earthy  substance, 
which  makes  them  stiff  and  hard, 
and  a  certain  amount  of  animal 
matter,  or  gelatine,  which  binds 
them  together  and  gives  them  a 
slight  degree  of  elasticity.  The 
earthy  substance  is  mostly  lime,  and  composes  about 
two  thirds  of  the  weight  of  the  bone.*  In  child- 
hood the  bones  are  more  largely  composed  of  ani- 
mal matter  than  in  old  age.  On  this  account,  chil- 
dren are  less  likely  to  have  their  bones  broken  by 


Fig.  i6.  —  Upper  portion 
of  the  right  femur,  sawn 
in  two  lengthwise,  show- 
ing the  difference  of  text- 
ure between  the  shaft 
and  the  extremity. 


*  The  color  of  bone  in  the  living  person  is  a  pale-rose  tint,  inclin- 
ing in  early  life  to  red,  in  old  age  to  a  yellowish  white.  Bones  assume 
a  beautiful  white  when  deprived  of  the  oily  fluids  which  pervade  them. 
The  specific  gravity  of  fresh  bone  is  greater  than  that  of  any  other  ani- 
mal substance. 


8o  HOW   WE  LIVE. 

blows  and  falls  ;  but,  for  the  same  reason,  they  are 
more  likely  to  become  deformed  by  remaining  in 
an  improper  position.  The  legs  of  young  children 
are  often  bent  out  of  shape  by  too  much  use  of  them 
before  their  bones  are  firm  enough  to  support  the 
weight  of  the  body.  In  old  persons  the  bones  are 
so  brittle  as  to  break  very  easily,  and  when  broken 
they  do  not  readily  unite  again. 

Growth  and  Repair  of  the  Bones. — The  bones 
do  not  reach  their  full  development  before  the  age 
of  twenty-five,  and  in  persons  who  use  the  brain  a 
great  deal  the  skull  is  said  to  continue  its  growth 
much  longer.  The  continual  repair  of  worn-out 
parts  is  carried  on  in  the  bones  as  in  the  rest  of  the 
body."^  When  a  bone  is  broken  and  the  parts  are 
brought  together  again,  a  watery  substance  is  poured 
out  of  the  fractured  ends  until  the  break  is  closed 
by  a  gristly  formation.  In  due  time,  mineral  matter 
is  supplied  to  stiffen  the  gelatine  thus  provided,  and 
the  bone  is  finally  restored  to  its  original  form  and 
strength. 

Bones  of  the  Head. — The  bone  which  gives 
shape  to  the  head  and  protects  the  brain  which  lies 
within  is  the  skull.  It  is  rounded  on  top  somewhat 
like  the  large  end  of  an  ^gg,  and  in  front  and  on  the 
sides  it  has  openings  for  the  eyes,  the  nose,  and  the 
ears.  The  skull  is  composed  of  two  compact,  armor- 
like plates,  with  a  layer  of  spongy  bone  between 
them.     The  dome-like  top  is  the  best  possible  form 

*  If  any  red  coloring-matter,  such  as  madder,  be  mixed  with  the 
food  of  a  young  animal,  its  effect  will  appear  within  a  day  or  two  in  the 
changed  color  of  the  bones. 


ffOlV  THE  BODY  IS  ABLE   TO  STAND.       8 1 


tor  resisting  pressure.  The  spongy  layer  prevents 
the  jar  of  a  blow  being  felt  by  the  brain.  The  upper 
jaw  and  the  bones  of  the  nose  and  the  cheeks  belong 
to  the  skull,  and  are  immovable.  The  movements  of 
the  mouth  are  effected  by  means  of  the  lower  jaw. 

Sutures  of  the  Skull. — The  skull  is  made  up  of 
several  parts  joined  by  irregular,  saw-like  projec- 
tions and  depres- 
sions on  each  side, 
very  much  as  we 
can  lock  the  fin- 
gers of  our  two 
hands  together. 
These  lines  of  con- 
nection are  called 
sutures.  In  child- 
hood the  parts  of 
the  skull  are  not 
very  firmly  united,  but  as  the  person  grows  older 
the  union  becomes  more  and  more  complete.  The 
use  of  having  the  skull  m  several  parts  is  to  allow 
the  brain  to  grow  and  to  prevent  a  jar  from  affect- 
ing the  whole  skull. 

Bones  of  the  Trunk. — The  bones  of  the  trunk 
are  the  pelvis,  the  spmal  column,  the  ribs,  the  breast, 
bone,  the  shoulder-blade,  and  the  collar-bone.^    The 

*  Strictly,  the  shoulder-blade  and  the  collar-bone  form  a  class  by 
themselves.  "  The  Upper  Extremity  consists  of  the  Arm,  the  Forearm, 
and  the  Hand.  Its  continuity  with  the  trunk  is  established  by  means  of 
the  shoulder,  which  is  homologous  with  the  mnominate  or  haunch-bone 
of  the  lower  limb.  The  Shoulder  is  placed  upon  the  upper  part  and  side 
of  the  chest,  connecting  the  upper  extremity  with  the  trunk  :  it  consists 
of  two  bones,  the  Clayicle  and  the  Scapula,".  CGray'^  ''  Anatomy.**) 


Fig.  17. — The  skull,  showing  the  sutures. 


82 


HOW    WE  LIVE. 


pelvis,  situated  at  the  bottom  of  the  trunk  below  the 
abdomen,  affords  a  foundation  for  the  trunk  and  a 
solid  means  of  attachment  for  the 
legs.  It  consists  of  the  sacrum, 
the  coccyx,  and  the  two  hip-bones, 
arranged  in  the  form  of  a  basin.  ^^&&j 

Attached  to  the  pelvis,  and  ex- 
tending up  the  middle  of  the  back 
to  the  head,  is  the  spinal  column,  or 
backbone.  It  is  made  up  of  twenty- 
four  small,  flat  bones  called  verte- 
brcB,'^  placed  one  upon  another  with  a 
pad  of  rubber-like  cartilage  between 
each  two.  The  spine  is  the  main 
connecting  structure  of  bone  in  the 

body,  gives  shape 

to  the  trunk,  and 

contains  a  channel 

through    which 

passes  the  spinal 

cord,    an    impor- 
tant   center     of 

nerve  -distribu- 

tion.f 

The  ribs,  twen- 


The    pelvis, 


showing  the  hip-joint  ty-four  in  num- 
and  the  relative  posi-  ^^  ^^^  -^  ^^-^^ 
tions  of  the  spine  and  ^ 

the  femur. 


inclosing    the 


Fio.  19. 
The  spinal  column. 


*  Of  the  vertebroc,  seven  belong  to  the  neck,  twelve  to  the  back, 
and  live  to  the  loin.  The  sacrum  and  the  coccyx  are  consolidated  ver- 
tebrae, and  may  be  included  in  the  spinal  column. 

f  When  we  look  at  the  spine  from  the  side,  we  see  that  it  has  a 


IIOJV  THE  BODY  IS  ABLE   TO  STAND.       83 


chest.  They  are  attached  to  the  spinal  column  by 
a  kind  of  joint  which  allows  them  to  move  up  and 
down  enough  for  the 
purpose  of  breathing. 
In  front  the  upper  sev- 
en pairs  are  attached  to 
a  strong,  flat  bone  ex- 
tending up  and  down 
and  called  the  sternum^ 
or  breast-bone."^ 

Extending      down- 
ward   from    the   top  of    Fig.  20.— Bones  of  the  thorax,  showing: 
the    trunk    behind    the  the  shoulder-joint,  the  relative  posi- 

arms,  on  eacn  siae  01       ^^^^^  ^^^.^^  ^^  ^^^  ^^^^^^  ^^^  ^^^ 

the    spine,    is    a   strong          shape  of  the  ribs  in  a  healthy  chest. 

plate  of  bone,  shaped 

Uke  a  triangle  and  called  the  shoulder-blade,  or 
scapula.  From  the  part  of  the  shoulder-blade  near- 
est the  arm  to  the  upper  part  of  the  breast-bone, 
extends  a  slender  bone  shaped  much  like  the  italic/, 
and  called  the  collar-bone,  or  clavicle.  This  braces 
the  shoulder-blade  and  helps  to  keep  it  in  place. 

Bones  of  the  Arms. — The  single  long  bone  be- 
tween the  shoulder  and  the  elbow  is  called  the 
humerus.     Of  the  two  between  the  elbow  and  the 

double  curve  bending  back  from  the  neck  to  the  shoulders,  then  for- 
ward to  the  waist,  and  then  back  as  it  nears  its  lower  extremity.  A 
pivot-joint  connects  the  two  upper  vertebrae,  and  a  hinge-joint  connects 
the  vertebrae  with  the  skull,  enabling  us  to  turn  the  head  and  move  it 
backward  and  forward. 

*  The  lowest  two  on  each  side  are  not  attached  in  front,  and  are 
called  floating  ribs.    The  remaining  three  pairs  are  connected  by  bands 
of  cartilage,  and  are  called  false  ribs. 
6 


84 


HOW   WE  LIVE. 


wrist,  the  one  more  closely  joined  to  the  humerus 
is  the  ulna;  the  one  which  moves  around  the  ulna 
is  the  radius.  The  bones  of 
the  wrist  are  eight  in  num- 
ber. The  palm  of  the  hand 
contains  five,  and  the  bones 
of  the  fingers  and  thumbs 
can  be  readily  counted. 

Bones   of   the   Legs. — 
The  bones  of  the  legs  cor- 
respond almost  entirely  to 
those  of  the  arms.    That  be- 
tween   the   trunk   and   the 
-Bones  knee  is  the  femur.    The  pa- 
"f^*  te//a  covers  the  knee-joint, 
their  ordinary  The  main  bonc  between  the 
positions.        knee  and  the  ankle  is  the 
fzdiay   and    the    one  which 
braces  it  is  the  fibula.     The  ankle  contains  seven  ; 
and   there  are  five  in  the  body  of  the  foot.     The 
bones  of  the  toes,  like  those  of  the  fingers,  can  be 
easily  counted. 

Arch  of  the  Foot. — The  bones  of  the  foot  are 
arranged  in  such  a  way  as  to  form  an  arch.  When 
the  weight  of  the  body  is  thrown  upon  the  foot,  as 
in  walking  and  leaping,  the  top  of  the  arch  is  pressed 
downward,  and  the  bones  spread  outward,  making 
the  foot  wider  than  before.  In  this  way  the  body 
is  preserved  from  shocks  which  would  otherwise 
greatly  injure  it  * 

*  Tight  shoes,  and  shoes  made  of  coarse,  heavy  leather,  are  injuri- 
ous in  many  respects.     They  prevent  the  spreading  of  the  foot,  and 


Fig.  22. — Bones 
of  the  left  arm, 
showing  the  ul- 
na and  the  radi- 
us in  a  twisted 
position. 


HOW   THE  BODY  IS  ABLE   TO  STAND. 


85 


Bony  Cavities  of  the  Body. — The  cavities  of  the 
body  which  are  formed  and  protected  by  the  bones 
are  thus  seen  to  be  the 
skull,  the  chest,  and  the 
abdomen.  The  skull  con- 
tains the  brain,  which  is 
the  most  sensitive  organ, 
and  has  no  motion. 
Hence  the  skull  is  abso- 
lutely unyielding-.  The 
chest  not  only  protects 
the  organs  within,  but 
varies  in  size  to  accom- 
modate the  lungs  in  res- 
piration. Accordingly, 
it  is  not  only  strong,  but 
expansive.  The  pelvis  ^^^'  ^3 
supports  the  organs  of 
digestion,  and  for  this  purpose  is  shaped  like  a 
basin.  It  also  sustains  the  whole  body  on  the  pil- 
lars formed  by  the  legs.  It  is,  therefore,  thick  and 
unyielding. 

Bodily  Movements. 

How  the  Muscles  move  the  Bones. — The  cause 
of  motion  in  the  body  is  the  contraction  of  the  mus- 
cles.    In  the  hollow  muscles  the  result  of  contrac- 

change  the  act  of  walking  from  a  free,  springing  motion,  to  a  stiff,  un- 
natural gait.  The  bones  become  distorted  and  overlap  one  another,  pro- 
ducing permanent  deformity.  The  continued  pressure  upon  the  flesh 
produces  corns,  bunions,  and  ingrowing  toe-nails.  High  heels  throw 
the  weight  too  far  forward,  and  heels  placed  under  the  hollow  of  the 
foot  not  only  prevent  the  spring  of  the  arch,  but  quickly  produce  de- 
formity. 


Bones  of  the  legs,  in  theii 
relative  positions. 


86  B-QIV    WE  LIVE. 

tion  is  to  diminish  the  capacity  of  the  vessels  which 
the  muscles  form.  Where  the  muscles  connect  two 
bones,  the  contraction  draws  the  connected  bones 
toward  each  other.  The  lower  jaw  is  drawn  up- 
ward by  a  strong  muscle  called  the  masseter.  This 
is  attached  to  the  cheek-bone,  and  acts  directly  to 


G 


Fig.  24. — The  arrangement  of  bones  and  muscles  by  which  the  arm  is  bent : 
A,  the  radius  ;  B^  the  elbow  ;  C,  biceps  ;  E^  ulna ;  F^  triceps  ;  G^  shoulder- 
joint. 

bring  the  jaws  together.  The  arm  is  bent  by  a 
strong  muscle  called  the  biceps.  This  is  attached  at 
one  extremity  to  the  shoulder-blade,  and  at  the  other 
to  the  radius  just  below  the  elbow.*  The  opposite 
movement,  by  which  the  arm  is  straightened,  is 
caused  by  a  similar  muscle,  called  the  triceps,  on 
the  opposite  side  of  the  arm.     This,  however,  is  at- 

*  When  the  biceps  contracts,  the  radius  is  drawn  upward  toward 
the  shoulder ;  but,  as  the  tendon  of  the  biceps  is  attached  to  the  radius 
so  near  the  elbow,  it  plainly  requires  more  muscular  effort  to  bend  the 
arm  than  would  be  required  were  the  tendon  of  the  biceps  attached 
nearer  the  wrist.  The  enlargement  of  the  elbow-joint,  by  raising  the 
tendon  away  from  the  arm,  brings  it  more  nearly  at  right  angles  to  the 
radius,  and  thus  gives  it  more  effect  in  bending  the  arm  than  it  would 
have  were  it  parallel  to  the  radius. 


HOW   THE  BODY  IS  ABLE   TO  STAND.       8; 

tached  to  the  ulna.*  The  muscle  which  throws  one 
leg  across  the  other  reaches  from  above  the  hip  on 
the  outside  to  below  the  knee  on  the  inside,  and  is 
called  the  tailor's  muscle,  or  sartorius,  because  it  is 
the  one  which  a  tailor  uses  in  taking  his  peculiar 
position  on  the  bench.  Wherever  a  twisting  mo- 
tion is  to  be  produced,  there  is  a  similar  arrange- 
ment. A  rotary  movement  of  the  eyeball  is  pro- 
duced by  a  muscle  passing  through  a  pulley-like 
loop. 

How  Shocks  are  Distributed. — Every  one  knows 
that  when  a  person  needs  to  jump  from  a  high  place 
the  shock  felt  will  be  much  less  if  the  body  is  al- 
lowed to  bend  freely  than  if  it  is  kept  rigid.  The 
hand  of  a  catcher  who  wishes  to  feel  the  sting  of 
the  ball  as  little  as  possible  is  allowed  to  move  back- 
ward when  the  ball  is  caught.  It  will  be  readily 
seen  that,  if  in  these  cases  the  limbs  were  held  rig- 
idly in  a  straight  line,  the  firm  ends  of  the  bones 
could  not  fail  to  strike  heavily  against  each  other, 
much  as  the  buffers  of  two  railway-cars  do  when 
the  cars  collide.  But  when  the  joints  are  bent  and 
the  muscles  are  relaxed,  the  main  force  of  a  shock 
is  expended  in  further  bending  the  joints,  and  the 
shock  felt  by  the  limbs  in  the  direction  of  their 
length  is  very  slight. 

In  jumping,  if  we  strike  upon  the  toes,  the  shock 
is  first  moderated  by  the  arch  of  the  foot,  which  acts 
like  a  spring.  The  force  of  the  shock  is  further  dis- 
tributed at  the  ankles,  the  knees,  and  the  hips,  by 

*  This  antagonistic  arrangement,  and  this  alternate  action  of  the 
muscles,  are  essentially  the  same  in  all  the  hinge-joints. 


88  ffOlV   WE  LIVE. 

the  three  curves  in  the  spine,  and  lastly  at  the  joint 
which  connects  the  spine  with  the  skull. 

Hygiene  of  the  Bones. 

I.  The  food  and  drink  that  we  take  must  contain 
enough  lime  to  nourish  the  bones.* 

II.  In  childhood,  before  the  bones  harden,  they 
should  not  be  made  to  sustain  heavy  weights,  nor 
should  they  be  subjected  to  a  continuous  press- 
ure.f 

III.  Exercise,  giving  the  proper  amount  of  press- 
ure and  strain,  is  necessary  to  promote  the  growth 
and  nurture  of  the  bones. 

IV.  The  bones  of  the  foot  should  not  be  com- 
pressed so  as  to  prevent  the  free  spring  of  the  arch 
and  the  spreading  of  the  bones,  when  the  foot  is 
called  upon  to  sustain  the  weight  of  the  body. 

V.  No  tight  bands  should  be  worn  about  the 
ribs  to  interfere  with  the  movement  of  the  bones  in 
breathing. 

VI.  We  should  sit  and  stand  erect,  so  as  to  pre- 
vent the  distortion  of  the  bones  which  comes  from 
the  habit  of  bringing  the  shoulders  forward  and 
bending  the  head  down. 

VII.  We  should  avoid  resting  one  arm  higher 

*  Farmers  have  long  noticed  that  cattle  often  do  not  thrive  in  an 
old  pasture.  Their  bones  become  tender  and  are  easily  broken,  and 
the  whole  body  suffers  in  health.  The  reason  is  that  those  elements  of 
the  soil  that  make  bones  have  been  used  up,  and  the  remedy  is  to  sup- 
ply fertilizers  that  contain  lime. 

f  A  baby's  legs  are  often  made  crooked  by  trying  too  early  to  make 
it  walk.  In  school,  many  a  child  has  been  deformed  by  sitting  on  so 
high  a  bench  that  its  feet  can  not  touch  the  floor. 


HOW   THE  BODY  IS  ABLE   TO  STAND.      89 

than  the  other,  as  this  practice  tends  to  produce  a 
permanent  curvature  of  the  spine. 

VIII.  When  a  bone  is  injured  or  a  joint  sprained, 
we  should  keep  perfectly  quiet  until  the  part  is  fully 
recovered. 

Something  to  Find  Out. 

1.  What  are  the  appearance  and  composition  of 
a  bone  after  it  has  been  thoroughly  burned  ? 

2.  What  are  the  appearance  and  condition  of  a 
bone  after  it  has  been  soaked  in  diluted  muriatic  acid  ? 

3.  In  making  soups,  what  ingredient  is  derived 
from  the  bones,  and  how  is  this  ingredient  obtained  ? 

4.  What  is  the  comparative  effect  of  a  sudden 
blow  upon  the  bones  of  young  and  of  old  persons  ? 
What  is  the  effect  of  pressure  ? 

5.  When  bones  are  broken,  what  are  some  of  the 
conditions  necessary  for  their  repair  ? 

6.  In  what  plays  is  there  particular  danger  of 
getting  bones  broken  ? 

7.  Why  is  the  skull  at  the  top  rounded  in  the 
shape  of  a  dome  ? 

8.  What  animal  is  so  constructed  that  its  upper 
jaw  can  be  thrown  back  ? 

9.  Why  is  the  pelvis  a  large  and  very  strongly 
constructed  bone  ? 

10.  What  is  the  use  of  the  rubber-like  cartilages 
between  the  vertebrae  of  the  spinal  column  ? 

11.  After  a  day  of  active  exercise  in  work  or 
play,  why  are  we  shorter  than  when  we  first  arose 
in  the  morning  ? 

12.  What  effect  does  wearing  a  tight  band  around 
the  waist  have  upon  the  shape  of  the  ribs  ?  upon 


go  HOW   WE  LIVE. 

the  movement  of  the  ribs  ?  upon  the  movement  of 
the  diaphragm?  upon  breathing?  upon  the  posi- 
tion of  the  organs  of  the  chest  and  abdomen  ?  upon 
the  circulation  of  the  blood  ? 

13.  Why  should  the  soles  of  shoes  be  broad? 
Why  should  the  heels  be  broad  and  low?  Why 
should  the  upper  leather  be  soft  and  pliable  ? 

14.  Why  do  people  wear  tight  clothing  and  tight 
shoes  ? 

15.  What  reason  is  there  for  making  shoes  with 
high  heels,  or  with  the  heel  in  the  hollow  of  the 
foot? 

16.  In  what  way  are  corns  produced  ? 

17.  What  name  is  applied  to  the  lower  limbs 
when  the  bones  have  become  permanently  bent  ? 

18.  In  the  bones  of  the  lower  arm,  which  bone  is 
attached  at  the  elbow,  and  which  at  the  wrist  ? 

19.  When  you  saw  in  two,  lengthwise,  a  beef  or 
mutton  bone  taken  out  of  the  leg,  how  does  the 
interior  appear  ? 

20.  Why  are  the  bones  and  joints  of  the  toes  so 
frequently  deformed  ? 

21.  Why  does  a  person  in  catching  a  ball  draw 
his  hands  back  the  moment  the  ball  touches  them  ? 

22.  Why  do  we  strike  on  the  ball  of  the  foot 
when  we  jump? 

23.  Why,  in  walking  or  jumping,  is  it  best  to 
keep  the  joints  bent  ? 

24.  When  we  unexpectedly  step  down  a  few 
inches,  what  effect  is  produced  ?     Why  ? 

25.  Why  do  so  many  people  have  a  stiff,  awk- 
ward gait  ? 


CHAPTER  VIII. 

HOW  THE   BODY   IS  COVERED. 

The  Usefulness  of  the  Bodily  Covering. — Every 
one  who  has  met  with  an  accident,  by  which  a  piece 
of  the  skin  has  been  torn  off,  can  understand  how 
important  it  is  that  there  should  be  some  sufficient 
protection  to  the  muscles  and  other  sensitive  organs 
which  lie  near  the  surface  of  the  body.  Besides  the 
pain  caused,  the  removal  of  the  skin  allows  poison- 
ous or  irritating  substances  to  enter  and  injure  the 
body.  In  addition  to  these  well-known  protective 
uses,  there  are  many  other  offices  which  the  skin 
performs.  It  assists  in  removing  waste  matter  from 
the  system,  absorbs  matters  brought  in  contact  with 
it,  is  the  termination  of  the  nerves  of  touch,  aids  the 
lungs  in  taking  in  oxygen  and  giving  out  carbonic 
acid,  regulates  the  temperature  of  the  body,  and,  in 
general,  not  only  defends  the  organs  within,  but 
helps  them  when  they  are  unable  to  do  their  full 
amount  of  work.  It  also,  with  the  hair  and  its 
other  appendages,  does  much  to  beautify  the  per- 
son and  give  expression  to  the  emotions  and  the 
thoughts. 


92  HOW   WE  LIVE, 

The  Skin. 

General  Structure  of  the  Skin. — The  thickness 
of  the  skin  varies  in  different  parts  of  the  body. 
Where  it  is  much  exposed  to  wear,  as  on  the  soles 
of  the  feet  or  the  palms  of  the  hands,  it  becomes 
very  thick  and  is  called  a  callus!^  In  other  parts  it 
is  very  thin  and  delicate.  At  the  ends  of  the  fin- 
gers and  the  toes,  where  unusual  protection  is  re- 
quired, it  grows  into  shield-like  plates  called  nails. 
On  the  scalp,  where  special  protection  of  the  brain 
is  needed,  it  puts  forth  a  thick  covering  of  hair. 

Layers  of  the  Skin. — The  skin  is  divided  into 
two  principal  layers.  The  outer  one  is  called  the 
scarf-skin,  cuticle,  or  epidermis.  It  is  made  up  of  little 
cells  flattened  into  scales.  It  has  no  blood-vessels  or 
nerves,  and  may  be  cut  or  pinched  without  giving 
pain.  As  the  cells  near  the  surface  become  dry  and 
hard  from  lack  of  nourishment,  they  fall  off  and  new 
ones  from  beneath  take  their  place.f  The  lower 
part  of  the  scarf-skin  contains  the  pigment,  or  color- 
ing-matter, which  determines  the  color  of  different 
races  and  different  individuals. :j:     The  inner  layer 

*  When  this  thickened  skin  is  at  the  same  time  continually  sub- 
jected to  hard  pressure,  as  by  tight  shoes,  it  forms  an  excessively  hard, 
horny  lump  called  a  corn.  Any  means  of  softening  the  lump,  as  soak- 
ing it  in  warm  water,  together  with  the  removal  of  the  cause,  will  often 
remedy  the  evil. 

f  It  is  these  worn-out  cells,  or  scales,  that  separate  from  the  skin  in 
bathing.  They  also  constitute  the  dandruff -which,  forms  on  the  head 
and  comes  off  in  small,  white  particles,  especially  when  the  hair  is 
combed  or  brushed. 

X  When  the  amount  of  coloring-matter  in  the  pigment-cells  is  very 
slight,  it  produces  a  blonde  complexion  ;  when  greater,  a  brunette. 


HOW   THE  BODY  IS  COVERED. 


93 


of  the  skin  is  called  the  true  skin,  cutis  vera,  or  derma. 
The  part  of  this  nearer  the  surface  is  composed  of 


Fig.  25. — Vertical  section  of  the  skin,  magnified  :  «,  scarf-skin  ;  3,  pigfment- 
cells ;  c,  papillae  ;  </,  true  skin  ;  e^  /,  fat  cells  ;  g^  sweat-glands  ;  h,  out- 
lets of  sweat-glands ;  ?,  their  openings  on  the  surface  of  the  skin  ;  ^,  hair- 
follicle  ;  /,  hairs  projecting  from  the  skin  ;  w,  hair-papilla  ;  «,  hair-bulb ; 
o,  root  of  hair  ;  p,  openings  of  oil-glands. 

The  colors  of  the  different  races  depend  upon  the  kind  and  amount  of 
pigment  in  these  cells.  The  amount  of  coloring-matter  is  increased  by 
exposure  to  heat  and  light.  Every  one  knows  that  those  who  spend 
much  time  in  the  open  air,  especially  in  summer,  become  tanned  and 
freckled,  and  that  when  winter  comes  again,  or  they  remain  in-doors 
for  a  time,  the  tan  and  freckles  mostly  pass  away.  This  is  because  the 
light  and  the  heat  increase  the  pigment.  When  this  takes  place  in 
spots,  it  causes  freckles  only ;  when  it  affects  the  whole  exposed  surface, 
it  causes  tan. 

When  persons  of  a  light  complexion  go  from  countries  distant  from 


94  ^OW    WE  LIVE. 

little  elevations  called  papillce.  These  contain  blood- 
vessels and  nerves,  and  from  some  of  them  arise  the 
hair-follicles,  or  the  openings  through  which  the 
hairs  reach  the  surface  of  the  skin.  Below  the  pa- 
pillae lies  the  main  part  of  the  true  skin  ;  and  be- 
tween the  true  skin  and  the  flesh  is  a  layer  of  fat, 
which  varies  in  thickness  in  different  persons. 

How  the  Skin  is  kept  Soft. — All  over  the  sur- 
face of  the  body  are  little  tubes  which  descend  into 
the  true  skin,  like  the  finger  of  a  glove  with  the  end 
downward.  Some  of  these  tubes  end  in  little  bags 
somewhat  resembling  clusters  of  grapes.  These 
groups  of  bags  are  called  sebaceous  glands!^  They 
collect  oil  from  the  blood  and  pour  it  out  through 
the  hair-follicles  upon  the  scarf-skin  to  keep  its  cells 
from  faUing  off  too  rapidly,  and  in  this  way  the 
skin  and  the  hair  are  kept  soft  and  pliable. 

How  the  Skin  casts  out  Waste  Matter. — In  the 
layer  of  fat  beneath  the  true  skin  lie  the  coiled  ends 
of  tubes,  which  reach  to  the  surface  of  the  skin. 
These  filter  off  from  the  blood  the  perspiration,  and 
are  called  the  sweat-glands.^     The  perspiration  con- 

the  equator  into  the  very  warm  regions  between  the  tropics,  they  be- 
come almost  as  dark  as  the  native  inhabitants.  When  the  natives  of 
very  hot  countries  live  for  a  long  time  m  cooler  latitudes,  their  com- 
plexion gradually  becomes  lighter.  In  some  persons  the  pigment  is 
entirely  wanting.  Such  persons  have  a  pallid  complexion  and  pink 
eyes,  and  are  called  albinos. 

*  The  oily  contents  of  these  glands  sometimes  harden  and  form  the 
black  specks  which  appear  in  the  skin. 

\  A  magnifying-glass  will  disclose  on  the  ridges  on  the  palm  of  the 
hand  over  three  thousand  openings  of  the  sweat-tubes  in  every  square 
inch.  There  are  also  great  numbers  on  the  soles  of  the  feet ;  and  even 
where  least  numerous,  as  on  the  back,  there  are  about  four  hundred 


HO IV   THE  BODY  IS  COVERED.  95 

sists  chiefly  of  water,  but  contains  also  a  certain 
amount  of  waste  material.  In  this  way  the  skin 
aids  in  keeping  the  body  free  from  impurities. 

Other  Means  of  casting  out  Waste. — A  consid- 
erable part  of  the  waste  matter  of  the  body  passes 
off  through  the  kidneys.  These  organs  lie  in  the 
abdominal  cavity,  one  on  each  side,  just  below  the 
*'  small  of  the  back."  They  absorb  from  the  blood 
impurities  which  can  not  be  expelled  at  the  lungs. 
The  waste  which  passes  off  through  the  kidneys 
and  through  the  skin  is  much  alike,  and  in  their 
action  they  assist  each  other.  When  the  kidneys 
are  diseased,  the  skin  does  more  work ;  and  when  the 
skin  is  out  of  order,  as  from  the  effects  of  a  cold, 
the  kidneys  become  more  active. 

How  the  Skin  regulates  Heat. — It  is  a  familiar 
fact  that,  in  very  warm  weather,  the  heat  of  a  room 
can  be  lessened  by  sprinkling  the  floor.  This  is  be- 
cause heat  is  used  up  in  changing  the  water  into 
vapor,  and  so  is  not  able  to  increase  the  tempera- 
ture. The  same  is  true  of  the  perspiration  which 
is  thrown  out  from  the  sweat-glands.  Usually  the 
perspiration  is  poured  out  so  gently  that  it  is  not 
noticed,  and  is  said  to  be  insejtsibleJ^  But,  in  very 
warm  weather,  or  when  the  body  is  heated  by  exer- 

present  to  every  square  inch  of  surface.  Indeed,  it  has  been  calculated 
that  there  are  twenty-eight  hundred  sweat-glands,  on  the  average,  in 
every  square  inch  of  the  body,  making  a  total  in  an  average-sized  man 
of  about  seven  million,  which  is  equivalent  to  twenty-eight  miles  of 
the  tubing,  since  each  tube  is  a  quarter  of  an  inch  long. — ("  The  Skin 
and  its  Troubles.") 

*  The  insensible  perspiration  of  an  adult  person  amounts  to  about 
twenty  ounces  in  twenty-four  hours. 


96  HOW   WE  LIVE. 

cise,  it  forms  visible  drops.  The  more  rapidly  the 
perspiration  flows  out,  and  is  changed  to  vapor,  the 
less  we  feel  the  heat.*  But  we  need  to  drink  much 
more,  in  order  to  keep  a  proper  amount  of  moisture 
in  the  body. 

How  the  Skin  Absorbs. — The  true  skin  contains 
a  great  number  of  blood-vessels,t  which  distribute 
nourishment  to  the  papillae,  the  roots  of  the  hair, 
the  oil-glands,  and  the  other  parts  of  the  skin ;  and 
which  carry  back  the  exhausted  blood  to  the  heart. 
It  also  contains  lymph-vessels,  which  commence  as 
little  spaces  between  the  cells  and  fibers  of  the  skin, 
and  gradually  form  tiny  tubes  to  carry  away  the 
lymph  into  the  blood.  Whenever  any  substance 
soaks  through  the  scarf-skin,  it  is  caught  up  by  the 
lymph-vessels  and  the  veins,  and  is  hurried  away  to 
various  parts  of  the  system.  X 

Why  the  Skin  should  be  kept  Clean. — It  is  plain 
that  the  natural  waste  of  the  scarf-skin,  and  the 

*  It  is  on  this  account  that  "  fire-kings  "  can  remain  in  ovens  heated 
as  high  as  600°. 

f  The  presence  of  red  blood  in  these  blood-vessels  gives  to  the  skin 
its  ruddy  color.  When  from  any  cause  the  blood  rushes  to  the  skin, 
this  ruddiness  is  increased.  When  this  rush  of  blood  is  supposed  to 
be  caused  by  some  emotion,  the  effect  is  known  as  blushing.  When 
from  any  cause  the  blood  is  withheld  from  these  vessels,  its  absence  is 
known  as  pallor,  or  paleness. 

X  The  power  of  the  skin  to  absorb  is  illustrated  by  the  fact  that 
persons  have  been  kept  alive  by  baths  of  soup  and  other  nourishment. 
It  may  have  been  for  a  similar  purpose  that  baths  of  wine  have  been 
sometimes  used  by  luxurious  persons.  On  the  other  hand,  it  is  well 
known  that  persons  whose  work  compell  them  to  handle  poisonous 
substances  frequently  lose  their  health  by  continual  contact  with  the 
materials  used.  Similar  effects  are  sometimes  produced  by  so  slight  a 
cause  as  a  kiss  from  one  who  is  affected  by  disease. 


HO IV  THE  BODY  IS  COVERED, 


97 


pouring  out  of  oil  and  perspiration  from  the  glands, 
must  result  in  the  accumulation  of  much  impurity 
upon  the  surface  of  the  skin.  It  is  plain,  also,  that 
if  this  mass  of  impurity  is  allowed  to  remain,  it 
must  not  only  be  in  itself  offensive,  but  must  de- 
range the  action  of  the  organs  of  the  skin.  The 
amount  of  impurity  thus  thrown  out  of  the  body  is 
much  increased  by  any  unusual  excitement  of  the 
nerves  caused  by  excessive  emotion.  Besides  these 
collections,  the  dust  and  dirt  which  come  upon  the 
skin  in  the  course  of  our  ordinary  work  require  fre- 
quent removal.  If  these  impurities  are  not  speedily 
removed,  they  derange  the  action  of  the  skin,  and, 
through  the  skin,  the  comfort  and  capacity  of  the 
whole  body."* 

How  to  keep  the  Skin  Clean. — The  only  means 
of  keeping  the  skin  clean  is  frequent  and  thorough 
bathing  of  the  entire  body.  This  should  be  attend- 
ed to  every  day,  if  possible.  If  from  any  cause 
this  frequency  is  not  possible,  the  nearest  approach 
to  it  should  be  made.  Under  any  ordinary  circum- 
stances, such  a  bath  may  be  taken  by  every  person  at 

*  Other  animals  show  us  the  good  of  being  clean  :  a  badly  groomed 
horse  is  never  sound  or  spirited,  and  a  dirty  pig  puts  up  one  fourth 
less  flesh  than  a  clean  one.  Yet  it  may  be  feared  that  some  hu- 
man beings  are  only  thoroughly  washed  at  birth  and  at  burial. — 
(Mapother.) 

Many  an  evil  action  is  the  remote  result  of  a  neglect  of  cleanliness. 
When  it  is  habitual,  it  brings  about  a  degraded  state  of  mind ;  and, 
even  when  it  is  temporary,  its  irritating  effect  upon  the  disposition  is 
often  noticeable.  It  is  a  fair  question  whether,  in  many  cases,  a  bad 
boy  might  not  be  converted  into  a  good  one  by  means  of  a  bath  and 
a  change  of  clothes.  The  public  baths  in  many  cities  are  really  very 
important  agencies  in  suppressing  wrong-doing. 


98  ^OlV   WE  LIVE. 

least  once  a  week.  Besides  this  bathing  of  the  whole 
body,  those  parts  which  especially  need  it  should  be 
washed  as  often  as  any  impurity  is  discovered  upon 
them.  For  merely  cleansing  the  body,  tepid  or 
warm  water  is  the  most  effective.  But  such  a  bath 
is  relaxing  in  its  effect,  and  should  not  be  used  very 
often.  The  cold  morning-bath  is  very  beneficial  to 
perfectly  healthy  persons,  not  only  for  its  cleansing 
power,  but  also  for  its  stimulating  effect.  If  a  bath- 
tub is  used,  a  simple  plunge  will  in  most  cases  be 
sufficient.  The  most  convenient  and  profitable  morn- 
ing-bath within  the  reach  of  a  majority  of  persons  is 
the  sponge -bath.  This  requires  only  a  basin  of 
water,  a  sponge  or  wash-cloth,  and  a  towel.  Only 
so  much  soap  as  is  necessary  should  be  used. 

If  the  skin  does  not  recover  its  warmth  in  a 
short  time  by  vigorous  rubbing  of  the  body  with 
a  coarse  towel,  the  person  is  not  in  proper  condi- 
tion to  profit  by  cold  baths.  The  other  forms  of 
bathing  are  either  medicinal  in  their  nature,  or  par- 
take of  the  nature  of  luxuries.* 

*  Sea-bathing  is  a  very  popular  form  of  the  natural  bath,  and  it  is 
preferable  to  bathing  in  river-water  or  spring-water,  because  the  sea  is 
seldom  so  cold  as  are  the  latter.  A  sea-bath  has  also  another  great 
advantage  over  all  other  forms  of  bath,  and  that  is  that  it  is  taken  in 
the  purest  air  possible  ;  and  in  considering  the  effects  of  sea-bathing, 
it  is  impossible  to  separate  the  effects  of  sea-air  from  that  of  the  sea- 
water.  The  sea-bather  is  also  constantly  inhaling  the  spray  of  the  sea- 
water,  and  thus  obtains  whatever  benefit  is  to  be  got  in  this  way.  If 
he  can  swim,  he  enjoys  all  the  benefit  of  exercise.  The  motion  of  the 
water  and  the  buffeting  he  gets  from  the  waves  act  as  a  powerful  ex- 
citant to  the  skin  ;  and,  lastly,  the  salt  in  the  water  adds  considerably 
to  the  stimulating  action.  Reaction  more  readily  occurs  after  a  sea- 
bath  than  after  a  river-bath. — ("  Baths  and  Bathing.") 


HOW   THE  BODY  IS  COVERED,  ^ 

No  kind  of  full  bath  should  be  taken  within  less 
than  two  hours  after  a  hearty  meal,  because  the 
process  of  digestion  will  not  allow  so  much  distrac- 
tion of  bodily  energy.  The  soap  used  in  bathing 
should  not  be  very  strong,  because  such  soap  will 
remove  too  much  of  the  scarf-skin,  and,  in  cold 
weather  especially,  will  cause  the  skin  to  chap. 

The  Hair. 

What  it  Is. — The  follicles  from  which  the  hairs 
grow,  and  the  oil-glands  which  cling  to  their  roots, 
have  already  been  mentioned.  The  hairs  them- 
selves are  modified  forms  of  the  scarf-skin.  Human 
hairs  are  solid,  but  the  central  parts  are  made  up  of 
cells  loosely  packed  together  to  form  a ////^.  The 
shaft  of  a  hair  is  the  part  outside  the  skin.  The  root 
is  the  part  which  lies  below  the  surface.  At  the 
side  of  the  hair  are  little  muscles,  by  which  it  may 
be  made  to  "stand  on  end."  The  color  of  the  hair 
is  due  to  a  pigment  in  the  cells.  The  flatter  the 
hairs  are,  the  more  readily  they  curl.* 

How  to  keep  the  Hair  Healthy. — The  health  of 
the  hair  depends  mainly  on  the  general  health  of 
the  body.  A  shght,  continuous  shedding  of  the 
hair,  especially  in  the  spring  and  autumn,  does  not 
indicate  ill  health.    The  hair  should  always  be  kept 

*  The  hair  upon  the  head  and  the  face  protects  from  cold,  and 
shields  the  head  from  the  rays  of  the  sun  in  hot  climates.  It  also 
breaks  the  force  of  a  blow  upon  the  head.  The  eyebrows  prevent  the 
perspiration  from  running  from  the  forehead  upon  the  lids.  The  eye- 
lids protect  the  eyes  from  dust  and  other  injurious  matters.  The  short, 
stiff  hairs  of  the  ears  and  the  nose  are  also  for  protection  to  these  open- 
ings. 


lOO  I/O IV    WE  LIVE. 

clean  by  frequent  washing,  and  by  thorough  but 
not  rude  brushing.  Cutting  the  hair  tends  to  pro- 
mote its  growth.  Great  care  should  be  taken  to 
keep  the  scalp  from  undue  pressure  from  any  cause, 
and  any  covering  of  the  head  which  prevents  the 
free  access  of  air  is  to  be  avoided. 

Thinning  and  Grayness  of  the  Hair. — Whatever 
leads  to  weakness  of  the  body  will  injure  the  hair. 
Sometimes  early  grayness,  or  the  loss  of  the  hair,  is 
common  in  a  family.  Sometimes  they  result  from  a 
local  disease  of  the  scalp;  but  usually  they  indi- 
cate a  general  weakness  of  the  body,  or  some  over- 
tasking of  the  mind  or  the  emotions.  Severe  ill- 
ness, fear,  worry,  anxiety,  or  hard  mental  work, 
may  cause  either  of  these  results.*  Various  hair- 
dyes  and  similar  preparations  are  sometimes  used 
to  restore  the  growth  or  the  color  of  the  hair ;  but 
most  of  them  contain  poisonous  substances,  which 
are  liable  to  enter  the  skin  by  absorption,  and  often 
produce  serious  results. 

Clot  J  ling. 

Why  the  Body  should  be  Clothed.— The  body 
needs  to  be  protected  by  clothing  as  much  as  the 
flesh  and  other  organs  need  the  protection  of  the 
skin.     Savages,  and  people  who  live  in  warm  coun- 

*  The  hair  may  become  white  or  gray  in  the  course  of  a  few  hours. 
In  most  cases  this  has  occurred  in  connection  with  intense  mental  emo- 
tion. The  cases  of  Marie  Antoinette  and  Sir  Thomas  More  are  widely 
known,  and  more  carefully  authenticated  cases  leave  no  doubt  that 
such  a  change  may  occur.  It  is  supposed  to  be  caused  by  the  entrance 
of  air  into  the  pith  of  the  shaft ;  but  how  its  entrance  there  is  effected 
is  difficult  to  imagine 


HOW  THE  BODY  IS  COVERED.  loi 

tries,  wear  much  less  clothing  than  those  who  are 
refined,  and  who  live  in  colder  climates.  Those 
who  go  without  shoes  come  to  have  the  skin  on 
their  feet  so  tough  and  thick  that  they  can  walk 
and  run  without  pain,  even  over  stony  surfaces; 
and  in  savages  somewhat  the  same  effect  is  pro- 
duced b}'  the  general  exposure  of  the  body.  But 
in  civilized  countries  the  general  use  of  clothing 
has  made  it  necessary,  not  only  as  a  protection 
from  hurt  and  from  extremes  of  heat  and  cold,  but 
also  as  a  means  of  adornment. 

How  the  Body  should  be  Clothed. — The  clothes 
we  wear  should  be  carefully  adapted  to  the  needs 
of  the  body  and  the  demands  of  good  taste.  Parts 
specially  exposed  to  injury,  as  the  feet,  need  the 
strong  protection  of  shoes ;  and  these  need  to  be 
heavy  or  light  according  to  the  service  which  they 
are  intended  to  perform.  The  head  needs  such  a 
covering  as  will  keep  it  warm  in  cold  weather,  and 
cool  in  warm  weather.  It  should  also  be  such  as 
will  shield  the  eyes  from  excessive  light.  Flannels, 
other  woolen  goods,  and  furs,  are  best  adapted  to 
retain  the  heat  of  the  body.  Hence  they  should 
be  used  in  cold  weather.  Cotton,  linen,  and  silk 
readily  conduct  the  heat  from  the  body,  and  should 
therefore  be  worn  when  the  weather  is  warm. 
Light  colors  reflect  much  heat  and  radiate  little ; 
hence  are  warmer  in  winter  and  cooler  in  summer.* 

*  Very  many  colds  are  caused  by  insufficient  clothing.  Whenever  a 
sense  of  chilliness  is  felt  in  any  part  of  the  body,  it  is  a  signal  from  the 
nerves  that  more  protection  is  needed ;  and  this  warning  should  be  heeded, 
no  matter  in  what  season  of  the  year,  or  at  what  time  of  day,  it  is  given. 


I02 


HOW    WE  LIVE. 


Special  care  should  be  taken  to  keep  all  parts  of 
the  body  absolutely  dry  at  all  times.     Whenever  it 


Fig.  26.— Deformity  of  the  ribs,  caused  by  wearing  clothing  tight  at  the  waist. 

is  necessary  to  walk  in  the  wet,  the  feet  should  be 
protected  by  overshoes,  and  water-proof  garments 
and  an  umbrella  should  always  be  used  when  they 
are  needed.  But,  as  overshoes  and  water-proofs  not 
only  keep  the  moisture  out,  but  also  prevent  the 
perspiration  from  escaping-,  they  should  never  be 
worn  in  dry  weather,  or  kept  on  in-doors.  If,  from 
unavoidable  causes — as  from  excessive  perspiration, 
being  caught  in  a  shower,  or  stepping  into  the  water 
■ — any  portion  of  the  clothing  becomes  wet,  it  should 
be  immediately  removed,  and  dry  clothing  should 
be  put  on.* 

*  The  neglect  of  these  simple  precautions  has  caused  almost  num- 


NO IV   THE  BODY  IS  COVERED.  103 

The  clothing  should  never  be  worn  so  tight  as 
to  interfere  with  the  entire  freedom  of  the  body. 
Very  tight  shoes,  and  tight  clothing  at  the  waist, 
are  the  two  most  serious  evils  in  modern  dress.* 

^  Hygiene  of  the  Skin. 

Since  the  skin  is  full  of  pores,  some  of  which 
give  off  waste,  and  some  of  which  absorb  matter 
from  the  outside,  it  is  very  important  that  these 
pores  be  kept  open.  As  the  skin  covers  the  en- 
tire body,  it  is  also  important  that  every  part  of 
it  should  be  kept  soft  and  elastic,  so  as  not  to 
press  uncomfortably  upon  the  delicate  organs 
beneath. 

From  these  facts,  and  from  the  foregoing  discus- 
sion, the  following  hygienic  laws  in  regard  to  the 
skin  become  obvious  : 

I.  The  skin  should  be  kept  clean,  so  as  to  allow 
waste  matter  to  be  readily  carried  off. 

II.  We  should  exercise  freely,  so  that  the  blood 
may  circulate  properly  in  the  skin. 

III.  The  skin  should  be  frequently  rubbed,  to 
help  the  circulation  of  the  blood,  to  excite  the  secre- 

berless  colds,  catarrhs,  and  more  serious  diseases.  Pneumonia  and 
consumption  often  originate  from  so  apparently  slight  a  cause  as  wear- 
ing insufficient  wraps  or  wetting  the  feet. 

*  The  apparent  tendency  of  the  times  to  more  freedom  in  these 
articles  of  dress  is  an  evidence  of  the  benefits  of  physiological  study  ; 
but  a  great  amount  of  instruction  is  still  needed.  Shoes  with  high 
heels,  by  throwing  the  feet  out  of  their  natural  position,  frequently 
cause  serious  injury  to  various  parts  of  the  body,  especially  the  eyes. 
Care  should  be  taken  to  avoid  any  article  of  clothing  which  contains 
poisonous  coloring-matter.  No  clothing  should  be  worn  which  leaves 
any  indication. of  color  upon  the  skin. 


104  //O^    IVE  LIVE. 

tion  of  oil  which  softens  the  skin,  and  to  keep  the 
scarf' skin  from  clogging  the  pores. 

IV.  Draughts  of  air  and  sudden  chills  should  be 
avoided,  as  they  drive  the  blood  away  from  the  sur- 
face, cause  the  skin  to  shrink,  and  close  up  the 
pores. 

V.  In  handling  poisonous  matter  of  any  kind,  we 
should  be  careful  not  to  let  it  come  in  contact  with 
the  skin,  lest  it  be  absorbed. 

VI.  When,  from  any  cause,  we  have  but  little 
vitality,  we  should  not  take  a  cold  bath,  because 
there  is  danger  that  reaction  may  not  follow. 

VII.  That  the  hair  may  be  vigorous,  it  should 
be  kept  clean,  and  brushed  often,  and  the  dry,  harsh 
ends  should  be  clipped  off. 

VIII.  The  scalp  should  be  kept  clean  and  be 
sometimes  gently  rubbed ;  then  it  will  supply  the 
hair  with  all  needed  nourishment,  and  will  render 
the  use  of  oil  and  "  hair-invigorators  "  unnecessary. 

IX.  Clothing  should  be  changed  with  the  tem- 
perature, to  protect  the  skin  from  extremes  of  heat 
and  cold. 

X.  Clothing  worn  next  to  the  skin  is  soon 
filled  with  waste  matter,  and  should  be  frequently 
changed.  The  same  clothing  should  not  be  worn 
day  and  night. 

XI.  The  clothing  should  not  be  worn  so  tight  as 
to  drive  the  blood  away  from  the  surface  of  the 
skin,  to  interfere  with  breathing,  or  to  prevent  the 
free  use  of  the  muscles. 


HOW   THE  BODY  IS  COVERED.  105 

Something  to  Find  Out. 

1.  Why  are  the  nails  upon  the  fingers  and  toes 
harder  than  other  parts  of  the  skin  ? 

2.  Why  is  the  skin  of  the  head  furnished  with  a 
thick  covering  of  hair  ? 

3.  What  becomes  of  the  waste  matter  contained 
in  the  "  insensible  perspiration  "  ? 

4.  How  much  waste  matter  is  thrown  off  from 
the  skin  in  one  year  ? 

5.  What  harm  comes  from  breathing  air  filled 
with  this  waste  matter  ? 

6.  Why  should  the  plaster  walls  and  ceiling  of  a 
school-room  be  frequently  whitewashed  with  lime  ? 

7.  Why  is  out-door  air  better  to  breathe  than  the 
air  of  inhabited  rooms  ? 

8.  How  may  the  air  of  inhabited  rooms  be  kept 
pure  ? 

9.  What  causes  the  peculiar  effect  upon  the  skin 
which  is  called  "  goose-flesh  "  ? 

ID.  When  "  goose-flesh  "  appears,  or  the  skin  be- 
comes suddenly  pallid,  what  should  be  done  ? 

11.  How  does  the  skin  appear  when  the  blood 
circulates  freely  through  it  ? 

12.  What  internal  organs  are  relieved  by  the  free 
circulation  of  the  blood  in  the  skin  ? 

13.  To  what  danger  are  nurses  exposed  by  be- 
ing with  persons  who  are  ill  ? 

14.  What  particular  danger  should  be  guarded 
against  in  surgical  operations  ? 

15.  Why,  in  taking  a  bath,  is  tepid  water  usually 
safer  than  cold  water  ? 


I06  ffOlV    WE  LIVE. 

1 6.  In  what  way  is  an  excessive  use  of  soap  in  a 
bath  injurious  ? 

17.  Why  is  a  boy,  when  dirty,  more  liable  to  do 
a  mean  thing,  than  when  he  is  clean  ? 

18.  Are  all  children  to  blame  for  an  untidy  ap- 
pearance ?     Should  they  be  reproached  for  it  ? 

(19.  Why  is  the  practice  of  wearing  fur  caps  and 
close-fitting  hoods  injurious  ? 

20.  What  kind  of  head-coverings  are  the  best 
for  summer  ? 

21.  What  peculiar  head-coverings  are  worn  by 
people  in  very  hot  climates  ? 

22.  Why  do  we  need  more  clothing  when  asleep 
at  night,  than  when  we  are  about  in  the  day-time  ? 

23.  Why  should  we  take  off  rubber  overcoats 
and  overshoes  immediately  on  coming  into  the 
house  ? 

24.  When  we  are  exposed  to  great  cold  or  heat, 
why  is  woolen  clothing  better  than  cotton  ? 

25.  When  our  feet  become  wet  and  cold,  how 
may  we  avoid  chilblains  ? 

26.  Why  do  people  in  the  Arctic  regions  dress 
in  the  skins  of  fur-bearing  animals  ? 

27.  In  case  of  a  slight  burn  or  a  scald,  what  part 
of  the  skin  rises  into  a  blister  ? 

28.  When  the  skin  is  burned,  why  should  the  air 
be  at  once  excluded  ? 

29.  Of  what  use  are  linseed-oil,  plasters  of  flour 
mixed  with  water,  and  plasters  of  clay,  in  case  of  a 
burn  ? 

30.  What  indicates  that  the  true  skin  has  been 
cut  or  burned  ? 


CHAPTER  IX. 

HOW  BODILY  MOTION   IS   DIRECTED. 

Bodily  Organs  must  act  in  Harmony. — If  each 
ol  the  internal  organs  of  the  body  should  move 
without  regard  to  the  movements  of  the  other 
organs,  life  could  not  exist ;  for  life  can  be  sustained 
only  by  all  the  organs  acting  together  in  harmony. 
If  each  of  the  external  organs,  as  the  arm  or  leg, 
were  independent  in  its  motions,  the  body  as  a 
whole  would  be  unable  to  do  any  useful  work,  and 
the  mind  could  not  carry  out  its  purposes  in  any 
direction.  In  order  that  nurture  may  go  on  in  the 
body,  and  that  the  mind  may  execute  its  plans,  all 
bodily  movements,  therefore,  must  be  under  orderly 
control.  This  control  is  effected  by  means  of  the 
nerves. 

TJie  Nervous  System. 

How  the  Nerves  are  Distributed. — Throughout 
the  body  there  is  a  nervous  system,  which  in  plan 
and  distribution  is  very  much  like  the  system  of 
blood-vessels.  The  nerves,  starting  from  a  nervous 
center,  divide  and  subdivide,  until  they  become 
exceedingly  minute,  hair-like  threads  extending  to 
every  organ  in  the  body-     In  the  skin  they  form  a 


io8 


HOW    IV E  LIVE. 


net-work  so  close  that  the  finest  needle  can  not 
pierce  the  skin  without  coming  in  contact  with 
some  of  them. 

Like  the  blood-vessels,  the  nerves  are  double,  one 
set  going  out  from  the  nervous  center,  and  the  other 
returning  to  it.  Unlike  the  veins  and  the  arteries, 
the  two  kinds  of  nerves  are  not  distinct,  but  their 
fibers  unite  so  closely  that  they  everywhere  appear 
as  a  single  thread. 

Nerve-Matter. — The  nerves  are  made  up  of  two 
kinds  of  matter,  white  and  gray.  Under  the  micro- 
scope the  white  matter  appears  as  minute  threads 
and  the  gray  as  tiny  cells.  The  white  matter  is 
much  greater  in  quantity  than  the  gray,  but  the  two 
are  found  together  in  all  the  nerves  of  the  body. 

The  Brain. — The  principal  nerve-center,  corre- 


FiG.  27. — The  brain  inclosed  in  its  membranes,  and  the  skull :  a,  6,  c,  con- 
volutions of  the  cerebrum ;  d,  the  cerebellum  ;  e,  medulla  oblongata ; 
/,  upper  end  of  the  spinal  cord  ;  ^,  A,  t\  A,  central  parts. 


HOW  BODILY  MOTION  IS  DIRECTED.      109 

spending  to  the  heart  in  the  circulation,  is  the  brain. 
It  occupies  the  whole  cavity  of  the  head,  and  is  care- 
full}^  protected  from  injury  by  the  skull.  The  front 
and  upper  part  of  the  brain,  about  seven  eighths  of 


Fig.  28. — Upper  surface  of  the  cerebrum,  showing  the  convolutions  of  the 
brain  and  its  double  structure. 

the  whole,  is  called  the  cerebrum;  the  back  and  lower 
portion,  the  cerebellum. 

The  interior  mass  of  the  brain  is  composed  of 
white  matter,  but  the  entire  surface  has  a  thin  cov- 
ering of  gray.  The  surface  of  the  cerebrum  is  made 
up  of  irregular  rounded  ridges,  or  convolutions,  giv= 
ing  to  it  a  large  amount  of  surface.*     In  the  cere- 

*  The  convolutions  of  no  two  brains  are  exactly  alike.  In  infancy 
they  are  scarcely  visible,  but  they  deepen  and  become  more  marked 
with  age.  In  the  civilized  races  the  brain  convolutions  are  deeper  and 
much  more  numerous  than  in  savages.  They  are  also  more  extensive  in 
a  studious  and  thoughtful  person  than  in  one  who  does  little  thinking. 
The  greater  the  number  and  depth  of  the  convolutions,  the  greater  is 


no  HOW   WE  LIVE. 

bellum  the  ridges  are  parallel  and  less  rounded.    A 
deep  indentation  extending  from  front  to  back  di- 


Fig.  29. — The  cerebrum,  the  cerebelhim,  the  spinal  cord,  and  the  general 
distribution  of  the  nerves. 

vides  the  brain  into  parts,  so  that  in  reality  the  brain 
is  double,  corresponding  to  the  pairs  of  the  external 

the  amount  of  brain-surface,  and  the  greater  the  amount  of  gray  matter 
which  covers  the  surface.  It  is  therefore  supposed  that  the  gray  mat- 
ter increases  with  study  and  thought,  and  with  any  active  business 
which  depends  upon  thinking  and  derriands  intelligent  control. 

It  is  estimated  that  in  some  of  the  most  perfect  human  brains  there 
•are  nearly  eight  hundred  square  inches  of  surface. 


HOW  BODILY  MOTION  IS  DIRECTED,      m 

portions  of  the  body.  From  the  nervous  mass  with- 
in the  skull  twelve  pairs  of  cranial  nerves  extend  to 
different  parts  of  the  head  and  face. 

The  Spinal  Cord. — From  the  brain  the  spinal 
cord,  the  great  center  of  nerve-distribution,  extends 
downward  through  the  spinal  column  to  the  lower 
extremity  of  the  trunk.  An  enlarged  part  of  this 
cord,  which  lies  next  to  the  cerebellum  and  extends 
below  it,  is  called  the  medulla  oblongata.  Thirty-one 
pairs  of  nerves  issue  from  the  spinal  cord  and  ex- 
tend to  the  different  parts  of  the  trunk  and  the 
limbs.     These  are  called  spinal  nerves. 

The  Ganglions. — Each  of  the  nerves  sent  out 
from  the  spinal  cord  is  in  two  parts,  one  coming 
out  of  an  opening  on  the  back  side  of  the  spinal  col- 
umn, and  the  other  from  a  similar  opening  in  front. 
These  parts  soon  unite  and  form  a  single  nerve,  and 
at  their  point  of  meeting  is  a  little  bunch  of  nervous 
matter  called  a  ganglion.  These  ganglions  form  a 
row  on  each  side  of  the  spinal  cord  ;  but,  as  each 
lies  in  the  course  of  a  single  nerve,  they  have  no 
direct  communication  with  each  other. 

Sympathetic  System. — Another  row  of  gangli- 
ons lies  on  each  side  of  the  spinal  column  deeper 
down.  They  are  connected  throughout  their  whole 
extent,  and  form  an  important  center  of  nervous 
force.  From  this  center,  nerves  extend  to  the  heart, 
the  lungs,  and  the  other  vital  organs.  Small  threads 
of  nervous  matter  serve  to  unite  these  ganglions  to 
the  nerves  that  issue  from  the  spinal  cord. 

Use  of  the  Nerves. — As  we  have  seen,  each 
nerve   issues   from  the  spinal  cord  in  two  parts ; 


112  HOW    WE  LIVE. 

and,  though  these  parts  unite  and  form  a  single 
thread,  each  part  has  a  distinct  function.  The  sec- 
tion which  issues  from  the  back  part  of  the  spinal 
cord  carries  to  the  brain  impressions  derived  from 
objects,  and  is  called  the  sensory  nerve;  the  one  that 
issues  from  the  front  part  carries  orders  from  the 
brain  to  the  muscles  so  as  to  direct  motion,  and  is 
called  the  motor  nerve. 

For  example,  the  naked  toe  comes  in  contact 
with  a  live  coal.  A  message  is  immediately  sent 
along  the  sensory  nerve  to  the  brain,  telling  the 
mind  that  the  toe  is  burning.  The  mind  at  once 
telegraphs  back  along  the  motor  nerve  to  the  proper 
muscle  an  order  to  draw  the  toe  away  from  its  dan- 
gerous position.  The  muscle  obeys,  and  the  toe  is 
saved. 

Direct  Nerve-Action. — When  the  mind  gives  a 
command  to  a  muscle,  the  message  starts  from  the 
brain,  and  we  are  conscious  both  of  the  order  given 
and  of  the  act  performed.  This  is  called  direct 
nerve-action.  To  perform  this  direct  action,  the 
mind  must  be  informed,  or  intelligent,  in  regard  to 
the  matter  in  hand.  It  must  have  a  clear  purpose, 
and  must  issue  a  clear  command.^ 

Reflex  Action. — Movements  of  the  vital  organs, 
over  which  the  mind  has  no  control,  are  constantly 

*  When  a  pupil  is  intent  on  the  study  of  a  subject,  and  takes  all 
possible  pains  to  understand  it,  the  mind  controls  every  step,  the  nerve- 
action  is  direct,  and  both  the  brain  and  the  mind  grow.  When  he  is 
engaged  in  learning  and  reciting  the  words  of  a  text-book,  with  little 
or  no  attention  to  the  thought,  the  mind  is  only  half  conscious,  the 
nerve-action  is  almost  automatic,  and  neither  the  brain  nor  the  mind 
is  benefited. 


I 


HOW  BODILY  MOTION  IS  DIRECTED.      113 

going  on,  and  there  are  many  movements  of  the  ex- 
ternal organs  which  are  automatic,  or  unconscious. 
Such  movements  have  their  origin,  not  in  the  brain, 
but  in  the  other  nervous  centers,  principally  in  the 
ganglions  and  the  spinal  cord.  This  unconscious 
movement  is  called  reflex  action. 

Reflex  action  has  control  of  the  vital  organs,  so 
that  the  processes  of  life  go  on  without  the  action 
of  the  will.  The  mind  has  no  direct  control  over 
the  action  of  the  heart,  the  liver,  or  any  other  of  the 
vital  organs.  Were  vital  action  under  the  control 
of  the  will,  the  mind  might  sometimes  forget,  and 
then  life  would  cease.  Reflex  action  has  also  gen- 
eral care  of  the  body  when  the  brain  is  at  rest  and 
the  mind  is  asleep."^ 

Sympathetic  Action. — While  the  lower  nervous 
centers  control  general  vital  action,  the  second  sys- 
tem of  ganglions  has  a  peculiar  function.  This  gan- 
glionic system,  as  a  nervous  center,  sends  nerves 

*  Breathing  is  partly  under  the  control  of  the  will.  We  can  sus> 
pend  our  breath  for  a  brief  time,  but  soon  the  motion  of  breathing  will 
be  resumed  in  spite  of  the  will.  A  case  is  on  record  of  a  man  who 
could  by  an  effort  of  his  will  control  the  beating  of  the  heart.  He  tried 
the  experiment  of  stopping  his  heart  "  once  too  often,"  and  it  never 
began  again. 

The  care  of  the  body  during  sleep  is  shown  when  the  hand  brushes 
away  a  fly  that  lights  on  the  nose,  but  does  not  waken  the  mind. 

Coughing  is  caused  by  spasms  of  reflex  action  operating  upon  the 
muscles  in  the  lungs.  When  a  bit  of  food  gets  into  the  trachea,  the 
cough-spasm  throws  it  out.  Diseases  of  the  lungs  produce  the  same 
feelings  as  the  presence  of  foreign  substances,  and  hence  lung-diseases 
are  accompanied  by  coughing.  Sneezing  is  a  similar  spasm  produced 
by  foreign  substances  or  disease  in  the  nose.  The  hiccough  is  a  nervous 
spasm  of  the  diaphragm,  caused  by  exhaustion,  as  from  excessive  laijgh' 
\ex.  or  from  the  effect  of  alcohoL 


114  i/0^   WE  LIVE. 

to  all  the  vital  organs,  and  these  organs  are  thus 
placed  in  direct  communication  and  sympathy  with 
one  another.  This  nervous  connection  is  called  the 
sympathetic  system.  When  the  stomach  is  out  of 
order,  the  sympathetic  nerve  gives  notice,  and  the 
heart  and  lungs  sympathize  and  become  deranged 
in  action.  Disturbance  in  one  organ  is  felt  in  all  the 
others.* 

Habit  and  Training. — In  every  action  which 
comes  from  thought,  the  mind,  through  the  brain, 
directs  the  first  steps.  When  the  actions  are  re- 
peated a  sufficient  number  of  times,  the  muscles  be- 
come accustomed  to  the  movement,  and  the  act  is 
performed  with  ease.  When  this  is  the  case,  the 
direction  of  such  acts  is  given  over  to  the  lower 
nervous  centers,  and  the  actions  are  performed  with 
little  or  no  consciousness. 

The  name  given  to  this  unconscious  repetition 
of  an  action  is  habit.\     The  precision  and  rapidity 

*  This  sympathy  gives  rise  to  many  needless  fears.  A  person  eats 
too  much,  and  the  stomach  labors  hard  to  get  rid  of  the  oppressive  load. 
In  sympathy  with  this  effort,  the  beat  of  the  heart  becomes  feeble  and 
irregular.  Then  the  terrible  fear  comes  that  the  heart  is  diseased,  and 
that  death  is  near.  The  doctor  comes,  laughs  at  the  fears,  gives  a  little 
mustard,  and  the  patient  is  well  the  next  day. 

The  use  of  tobacco  produces  "  heart-burn,"  a  trouble  of  the  stomach,  and 
this  in  turn,  through  sympathetic  action,  causes  palpitation  of  the  heart. 

f  Habits  once  formed  are  difficult  to  overcome.  Habits  formed  in 
youth  are  the  most  lasting.  The  old  man  is  slovenly  because  as  a  boy 
he  was  untidy.  The  fine  scholar  can  not  in  his  oration  entirely  get  rid 
of  the  inelegant  expressions  of  his  childhood.  The  cruel  boy  becomes 
the  brutal  man. 

Good  habits  are  equally  durable.  The  kindly  acts  of  the  boy  or 
the  girl  ripen  into  kindness  in  the  man  or  the  woman.  When  effort  to 
do  things  well  becomes  a  fixed  habit,  it  makes  life  rich  in  well-doing. 


HOW  BODILY  MOTION  IS  DIRECTED. 


115 


of  action  which  come  from  habit  constitute  skill ; 
and  the  method  by  which  skill  is  obtained  is  train- 
ing/^  The  training  which  converts  acts  into  habits 
relieves  the  mind  and  the  brain,  and  leaves  them 
free  to  study  new  things  and  to  perform  new 
acts. 

Exercise  of  the  Nerves. — Like  the  other  parts 
of  the  body,  the  nerves  require  exercise.  The  food 
furnishes  the  elements  of  nerve-growth,  but  exer- 
cise is  necessary  to  make  their  growth  vigorous  and 
to  secure  strength.  When  the  mind  is  engaged  in 
observing  objects,  finding  out  their  qualities,  and 
comparing  them  with  other  objects,  it  is  giving 
direct  exercise  to  the  sensory  nerves.  When  the 
hands  are  doing  something  under  the  direction  of 
the  mind,  the  motor  nerves  are  brought  into  exer- 
cise. In  both  these  cases,  and  in  all  thinking,  the 
brain  is  exercised. 

If  nerve-exercise  is  omitted,  the  whole  body  suf- 
fers, the  vital  organs  are  feeble  in  their  action,  the 
blood  moves  slowly  in  the  veins  and  the  arteries, 
waste  is  imperfectly  made  up,  the  muscles  become 
flabby  and  weak,  and  the  brain  is  so  little  nourished 
that  at  last  it  becomes  incapable  of  vigorous  action. 
The  starved  mind,  working  through  the  starved 
brain,  gradually  loses  the  vitality  it  had  at  first,  until 
it  becomes  little  better  than  idiotic.   To  prevent  this 

*  A  young  lady  beginning  to  play  the  piano  is  obliged  to  fix  her 
whole  attention  upon  the  position  of  her  hands  and  upon  the  keys  she 
is  to  strike.  When  training  has  given  her  skill,  she  strikes  the  keys  cor- 
rectly without  thinking,  and  she  is  able  to  give  her  whole  attention  to 
the  music.  In  like  manner,  skill  enables  the  workman  to  do  his  best 
work  with  the  least  conscious  attention. 
8 


Il6  HOW    WE  LIVE. 

result,  the  mind  requires  daily  activity  in  careful 
study,  or  in  directing  some  useful  work.* 

Rest  of  the  Nerves. — The  nerves  also  need  rest. 
Like  the  muscles,  they  become  tired  with  exercise. 
Nightly  sleep  furnishes  the  necessary  rest  for  proper 
daily  exercise.  If,  during  the  day,  the  nerves  are 
unduly  exercised  or  strained,  they  become  weary, 
and  sleep  does  not  restore  their  vigor.  If  the  strain 
is  continued,  sleep  is  broken,  the  weariness  in- 
creases, and  the  nervous  system  breaks  down,  leav- 
ing the  person  a  helpless  burden  to  others.  Ex-. 
cessive  study,  or  excessive  work  of  any  kind,  which 
requires  brain-labor,  often  results  in  congestion  or 
softening  of  the  brain,  or  in  paralysis. 

How  Alcohol  affects  the  Nerves. — Alcohol  and 
other  narcotics  have  a  tendency  to  paralyze  the 
nerves,  and  so  diminish  their  power  to  act.  This 
effect  first  shows  itself  in  the  nerves  which  con- 
trol the  passage  of  the  blood  through  the  small 
arteries.  The  half-torpid  nerves  can  not  sufficiently 
control  the  rush  of  the  blood,  and  the  minute  ves- 
sels are  gorged.  This  gives  to  the  skin  a  peculiar 
redness,  which  is  very  observable  in  the  dehcate 
skin  of  the  face.  The  brain  is  affected  in  a  similar 
manner,  and  is  gorged  with  blood,  causing  great 

*  The  nerves  are  greatly  affected  by  emotion.  By  a  joyous  and 
happy  mood  nervous  action  is  increased,  the  vital  organs  are  stimulated 
to  do  their  v\^ork  well,  and  a  glow  of  health  pervades  the  whole  body. 
Grief  diminishes  nervous  action.  Sudden  bad  news  sometimes  so  para- 
lyzes the  nerves  that  the  heart  ceases  for  a  time  to  beat,  and  faintness, 
or  even  death,  is  the  result.  Ill  temper,  envy,  sulkiness,  and  all  kinds 
of  selfishness  and  meanness,  diminish  nerve-force,  and  tend  to  derange 
the  action  of  the  vital  organs. 


'how  bodily  motion  is  directed.      117 

activity  and  tumult,  but  not  the  orderly  action 
which  produces  good  thinking  and  leads  to  useful 
doing. 

If  the  alcohol  is  continued  until  the  habit  of 
drinking  is  formed,  the  derangement  of  the  nerves 
becomes  more  marked.  The  heart  is  weakened  and 
grows  feeble  in  its  action  ;  the  nerves  lose  con- 
trol of  the  muscles  and  the  limbs  stagger ;  and  there 
is  a  general  derangement  of  all  the  organs,  because 
the  nerves  Avhich  ought  to  produce  harmony  of 
action  are  paralyzed. 

Effect  on  the  Mind. — The  cerebrum  is  the  seat 
of  intelligence  and  of  the  moral  nature.  Through 
the  cerebrum  the  mind  directs  and  controls  bodily 
action.  The  cerebellum  is  the  seat  of  the  nervous 
influence  that  more  immediately  affects  the  body, 
and  it  controls  the  regular  order  of  unconscious 
action,  like  walking.  Alcohol  much  more  quickly 
paralyzes  the  cerebrum  than  the  cerebellum.  In 
consequence,  when  drink  has  been  taken  in  excess- 
ive quantities,  both  the  intelligence  and  the  moral 
nature  are  dead  for  a  time,  and  the  appetites  and 
passions  have  full  sway.  In  this  way  a  man  is  often 
converted  into  a  brute,  dangerous  to  his  family,  to 
his  neighbors,  and  to  himself.  Continued  drunken- 
ness often  ends  in  delirium  and  death. 

How  Tobacco  affects  the  Nerves. — The  general 
use  of  tobacco  diminishes  nervous  action.  Its  ha- 
bitual use  is  not  so  destructive  as  that  of  alcohol, 
but  still  it  is  a  substance  which  enters  into  the  sys- 
tem without  furnishing  any  needed  element.  It  is 
in  the  body,  but  not  of  it.     When  used  to  excess,  it 


Il8  HOW    WE  LIVE. 

has  a  particularly  paralyzing  effect  upon  the  nerves 
which  control  the  muscles  of  the  heart,  weakening 
its  action  to  such  a  degree  as  often  to  cause  spasms 
and  insensibility. 

Inheritance. — Children  inherit  from  their  par- 
ents nerves  weakened  by  the  use  of  alcohol  and  to- 
bacco, and  the  lives  of  thousands  of  innocent  per- 
sons are  thus  made  miserable.  Usually  the  first 
drink  and  the  first  smoke  are  found  to  be  very  dis- 
agreeable, but  quite  often  an  inherited  appetite 
shows  itself,  and  the  sweet  breath  of  the  child  be- 
comes foul  with  the  whisky  and  tobacco  which  can 
not  be  kept  out  of  his  way.  Beginning  with  this 
unnatural  appetite,  habits  are  speedily  formed  which 
make  his  life  a  burden  to  himself  and  to  others. 

Hygiene  of  the  Nerves. 

As  the  nerves  control  all  the  movements  of 
the  body,  both  conscious  and  unconscious,  and  thus 
affect  its  nourishment,  we  need  to  take  the  greatest 
care  to  keep  them  healthy,  and  especially  to  avoid 
all  courses  likely  to  injure  them. 

I.  We  must  observe  all  the  laws  of  digestion,  so 
that  the  brain  and  the  nerves  may  be  supplied  with 
pure  blood. 

II.  We  must  avoid  breathing  foul  air,  or  the 
nerves  will  be  paralyzed  by  the  impurities  of  the 
blood. 

III.  To  keep  it  in  health,  the  brain  should  every 
day  be  brought  into  vigorous  action  by  some  form 
of  study  or  thinking. 

IV.  Active  daily  exercise,  by  either  work  or 


HO IV  BODILY  MOTION  IS  DIRECTED.      119 

play,  is  necessary  to  secure  the  healthful  action  of 
the  nerves  distributed  through  the  body. 

V.  We  need  a  great  variety  of  objects  to  ob- 
serve, to  handle,  and  to  study,  in  order  that  the 
sensory  nerves  may  receive  sufficient  exercise. 

VI.  We  need  a  great  variety  of  work,  having  the 
stimulus  of  a  useful  purpose,  that  the  motor  nerves 
and  the  brain  may  be  excited  to  healthful  action. 

VII.  When  we  are  tired  we  need  rest,  because 
as  much  nervous  force  as  we  can  spare  has  been 
used  up.  Sleep,  the  natural  rest  from  daily  toil, 
should  be  regular,  and  should  continue  until  the 
vigor  of  the  nerves  is  restored. 

VIII.  The  hardest  study  and  the  closest  think, 
ing  should  be  done  when  the  nerves  are  most  vig- 
orous, and  that  is  usually  during  the  first  half  of 
the  day. 

IX.  We  should  never  try  to  think  or  study 
when  we  are  sleepy.  In  the  first  place,  we  then 
need  sleep  more  than  knowledge ;  and,  in  the  sec- 
ond place,  we  gain  very  little  knowledge  when  the 
mind  is  weary. 

X.  We  should  avoid  continued  and  excessive 
mental  work,  because  it  may  become  so  exhausting 
as  to  break  down  the  whole  nervous  system. 

XI.  When  the  nerves  have  become  so  exhausted 
that  we  can  not  sleep,  we  must  give  up  all  labor 
and  thinking  until  the  nerves  have  recovered  their 
lost  strength. 

XII.  Cramming  for  an  examination  is  much 
more  exhausting  than  a  much  longer  period  of 
regular  study,  and  should  be  avoided. 


I20  I/O IV    IVE  LIVE. 

XIII.  We  should  try  to  do  those  things  which 
will  form  good  habits,  so  that  we  may  easily  and 
certainly  perform  good  deeds  throughout  life. 

XIV.  We  should  take  special  pains  to  avoid 
doing  anything  which  tends  to  form  bad  habits, 
because  it  will  be  always  difficult,  and  sometimes 
impossible,  to  correct  such  habits  when  they  have 
once  been  formed. 

Something  to  Find  Out. 

1.  In  study,  what  should  always  be  our  object? 

2.  In  the  study  of  science,  what  evils  come  from 
trying  to  learn  the  exact  words  of  a  text-book  ? 

3.  What  is  the  effect  ol  adding  careful  experi- 
ment to  the  study  of  a  subject  ? 

4.  In  case  we  do  not  understand  a  subject  that 
we  have  studied,  what  is  to  be  done  ? 

5.  Why  is  it  injurious  to  attempt  to  hold  the 
breath  for  any  considerable  time  ? 

6.  When  we  have  eaten  too  much,  what  symp- 
toms, besides  sickness  at  the  stomach,  may  we  ex- 
pect? 

7.  After  we  have  learned  to  walk,  what  nervous 
action  controls  walking  ? 

8.  What  trouble  would  come  if  the  cerebrum 
were  obliged  to  control  walking? 

9.  Why  is  it  easier  to  perform  an  act  the  second 
time  than  at  first  ? 

10.  What  is  the  result  of  doing  one  act  re- 
peatedly ? 

11.  When  we  perform  acts  without  much  think- 
ing, what  have  we  acquired  ? 


HOl^l^  BODILY  MOTION  IS  DIRECTED.      121 

12.  What  kinds  of  acts  lead  to  the  formation  of 
good  habits  ?  of  evil  habits  ? 

13.  What  does  a  person  need  in  order  to  be- 
come a  good  base-ball  player  ? 

14.  What  term  is  applied  to  persons  who  do  not 
like  to  exercise  either  body  or  mind  ? 

15.  What  good  do  we  get  from  play  that  we  do 
not  get  from  work  ? 

16.  What  good  results  from  work  that  does  not 
come  from  play  ? 

17.  Why  is  night  the  best  time  for  sleep? 

18.  What  good  comes  from  having  sleep  at  regu- 
lar hours  ? 

19.  Why  should  w^e  give  up  study  when  we  are 
sleepy  ? 

20.  What  kind  of  games  are  beneficial  to  stu- 
dents while  attending  school  ? 

21.  What   kind   of   games  would   rather  injure 
than  benefit  them? 

22.  Explam  how  a  game  may  be  beneficial  to  a 
farmer  when  it  would  injure  a  student. 

23.  What  class  of  people  is  most  benefited  by  a 
week's  fishing  in  summer? 

24.  What  good  comes  from  the  use  of  alcohol 
when  we  are  in  health?     From  the  use  of  tobacco? 

25.  How  does  alcohol  affect  speech? 

26.  Why  may  a  drunken  man  be  considered  in- 
sane? 

27.  In  what  way  can  we  best  avoid  the  dangers 
and  miseries  which  come  from  drunkenness  ? 

28.  How  may  we   escape   from   the   danger  of 
heart-trouble  caused  by  tobacco? 


CHAPTER   X. 

HOW  THE    MIND    GETS   IDEAS    AND    EXPRESSES 
THEM. 

Sensations. — The  sensory  nerves  receive  im- 
pressions from  objects  and  carry  them  to  the  brain. 
These  impressions  are  called  sensations.  When  the 
sensation  is  fully  known  to  the  mind,  it  is  called  an 
idea.  Since  the  skin  most  directly  comes  in  con- 
tact with  objects,  it  has  the  greatest  supply  of  sen- 
sory nerves.  From  nerves  in  the  muscles  we  get 
ideas  of  pressure  and  weight.  Through  the  nerves 
of  touch  in  the  skin  we  get  from  the  surface  of  ob- 
jects the  ideas  which  are  expressed  by  the  terms  hard 
and  soft,  rough  and  smooth,  hot  and  cold. 

But  these  ideas  are  not  enough.  The  mind 
needs  to  know  about  flavors  and  odors  ;  it  rnust  get 
from  sound  its  meaning  and  its  music  ;  and  from 
light  it  must  learn  the  beauty  of  form  and  color. 
For  these  purposes  some  of  the  sensory  nerves 
take  the  form  of  special  nerves  of  sense,  as  those  of 
taste,  smell,  hearing,  and  sight. 

The  Sense  of  Taste. 

The  Taste  as  a  Sentinel. — Special  care  must  be 
taken  that  improper  food  be  not  admitted  into  the 


HOW  THE  MIND   GETS  IDEAS.  123 

stomach.  The  mind  must  keep  close  watch  over 
all  things  eaten,  and  must  reject  such  as  will  be 
likely  to  injure  any  part  of  the  body.  One  of  the 
agents  which  the  mind  uses  to  determine  whether 
food  is  wholesome  or  unwholesome  is  the  sense  of 
taste. 

Flavors. — When  food  is  taken  into  the  mouth, 
it  gives  an  impression  which  we  call  flavor."^  The 
nerves  upon  which  flavors  make  an  impression  give 
us  the  sense  of  taste,  and  are  called  gustatory  nerves. 
They  are  distributed  over  the  tongue  and  the  back 
part  of  the  mouth.  Many  substances  taken  in  the 
mouth  may  be  felt  but  not  tasted.  Touch  takes 
notice  of  certain  quaUties  of  all  substances;  but 
taste  notices  flavors  only,  and  is  not  aroused  to 
activity  until  the  surface  of  the  substance  yielding 
the  flavor  is  dissolved  by  saliva.  We  can  get  no 
idea  of  flavor  except  through  the  gustatory 
nerves. 

Before  flavors  can  be  perceived,  the  substance 
must  come  in  direct  contact  with  the  nerve.  When 
a  strong  flavor  has  been  tasted,  the  impression  will 
remain  for  some  time,  and  will  prevent  other  flavors 
from  making  their  proper  impression.  Except  in 
disease,  the  flavor  of  most  wholesome  foods  is  pleas- 

*  The  primary  and  strongest  flavors  are  sweetness,  sourness,  saltness, 
and  bitterness.  Besides  these,  there  are  the  flavors  peculiar  to  difter- 
ent  fruits,  such  as  peaches,  grapes,  etc.,  and  the  flavors  peculiar  to  the 
different  varieties  of  the  same  fruit,  as  that  of  Catawba  and  of  Dela- 
ware grapes.  It  is  thought  by  some  that  all  possible  flavors  are  made 
up  of  different  combinations  of  the  four  primary  ones  ;  but  this  point  is 
not  settled. 


124  ^^^   ^^  LIVE, 

ant,  and  the  necessary  act  of  daily  eating  is  thus  ren- 
dered agreeable.* 

The  Sense  of  Smell. 

Odors. — Another  of  the  agents  employed  to  test 
foods  is  the  sense  of  smell.  When  certain  sub- 
stances are  brought  near  the  nose,  they  make  an 
impression  which  is  called  odor.  The  nerves  upon 
which  odors  make  an  impression  give  us  the  sense 
of  smell,  and  are  called  olfactory  nerves.f  These 
nerves  are  distributed  through  the  cavities  of  the 
nostrils.  Substances  smelled  do  not  come  in  con- 
tact with  the  olfactory  nerve.  Such  substances 
give  off  something  that  we  call  aroma,  or  odor.  In 
no  way  can  we  measure  or  weigh  odor.  It  is  only 
known  through  the  sense  of  smell.  Agreeable  odors 
give  us  a  sense  of  pleasure,  and  also  stimulate  the 
whole  nervous  system. 

*  The  sense  of  taste  is  not  a  perfect  guide  in  the  choice  of  foods. 
One  of  the  conditions  of  good  digestion  is  that  food  shall  be  palatable. 
But  palatable  food  is  not  always  wholesome,  and  the  mind  must  have 
other  means  of  deciding  what  shall  be  eaten. 

The  act  of  eating  is  agreeable  ;  but,  if  we  give  ourselves  up  to  the 
pleasures  of  the  appetite,  swine  have  an  advantage  over  us,  as  they  ap- 
pear to  enjoy  eating  even  better  than  we  do. 

f  The  olfactory  nerve  notices  nothing  but  odors.  Unpleasant  odors 
denote  the  presence  of  something  hurtful.  Food  that  is  tainted,  or  that 
gives  off  an  unpleasant  odor,  is  unfit  for  the  human  stomach.  Air  that 
smells  vile  is  unfit  to  breathe.  A  keen  sense  of  smell  is  very  desirable, 
and  it  will  be  well  to  always  "  follow  the  nose  "  when  it  leads  away 
from  bad  odors. 


-ikae 


HO  IV   THE  MIND  GETS  IDEAS,  125 

The  Sense  of  Hearing. 

Sound. — Whenever  an  object  of  any  kind  moves, 
a  portion  of  the  air  is  disturbed  and  set  in  motion. 
Whenever  an  object  has  a  continued  motion  to  and 
fro,  a  similar  wave-hke  motion,  or  vibration,  is  set  up 
in  the  air.  These  vibrations  strike  upon  the  ear,  and 
produce  an  impression  which  is  called  sound!^  The 
nerves  that  receive  impressions  of  sound  are  the 
auditory  nerves,  and  the  sense  that  has  sound  for  its 
object  is  the  sense  of  hearing. 

It  is  necessary  that  the  mind  should  know  what 
movements  are  going  on  around  it,  so  that  it  may 
avoid  danger,  and  take  advantage  of  circumstances 
to  carry  out  its  purposes.  It  should  be  able  to  dis- 
tinguish different  sounds  for  the  pleasure  that  music 
affords.  The  mind  must  also  be  able  to  distinguish 
and  produce  the  sounds  used  in  articulate  speech 
for  the  purpose  of  understanding  and  of  expressing 
thought.  These  ends  it  accomplishes  by  means  of 
the  ear. 

The  Ear. — The  ear,  which  is  the  organ  of  hear- 
ing, has  three  parts  :  the  outside  or  external  ear, 

*  The  least  number  of  vibrations  that  produce  a  sound  which  the 
ear  can  perceive  is  sixteen  per  second.  As  the  vibrations  increase  in 
rapidity,  the  sound  becomes  higher  in  pitch.  The  highest  sound  that 
the  ear  perceives  is  made  by  about  thirty-two  thousand  vibrations  per 
second.  Vibrations  below  sixteen  and  above  thirty-two  thousand  per 
second  are  silent  to  the  human  ear. 

The  sense  of  hearing  may  be  cultivated  so  that  the  ear  will  detect 
sounds  which  are  not  audible  to  other  ears,  and  will  observe  differences 
which  were  before  unnoticed.  This  cultivation  makes  life  richer  by 
the  new  enjoyments  which  it  affords. 


126 


HOW   WE  LIVE. 


which  we  see  ;  the  middle  ear,  or  tympanum,  which 
is  a  small  passage  through  the  bones  ;  and  the  in- 


Fig.  30. — The  parts  of  the  ear:  a,  external  ear;  5,  passage;  c,  membrane 
cf  the  tympanum  ;  d — m^  bones  and  their  connections ;  n — r,  interior 
canals  and  openings  ;  i,  2,  3,  small  bones  of  the  ear,  highly  magnified. 

ternal  ear,  which  consists  of  several  winding  pas- 
sages in  the  bony  structure  of  the  skull.  The  three 
parts  of  the  ear  are  separated  by  thin  membranes 
which  stretch  across  each  end  of  the  tympanum 
like  the  head  of  a  drum.  A  passage,  called  the 
Eustachian  tube,  opens  from  the  tympanum  into  the 
throat.* 

The  vibrations  of  the  air  striking  the  outer  mem- 

*  Through  the  Eustachian  tube,  air  is  admitted  to  the  inside  of  the 
tympanum,  so  that  the  pressure  upon  both  sides  of  the  **  ear-drum  "  is 
equal.  When  we  have  a  cold  and  the  throat  is  swollen,  the  mouth  of 
this  tube  is  closed,  and  we  become  quite  deaf  for  a  time.  The  remedy 
is,  not  to  doctor  the  ears,  but  to  cure  the  throat. 


I/OJV   THE  MIND   GETS  IDEAS.  127 

brane  of  the  tympanum  cause  it  to  vibrate,  and  the 
motion  is  conveyed  to  the  auditory  nerve,  which  is 
spread  over  the  passages  of  the  internal  ear.  This 
gives  the  impression  of  sound.  The  quahty  and  in- 
tensity of  the  vibrations  are  in  some  measure  regu- 
lated by  a  chain  of  minute  bones  within  the  tym- 
panum, and  by  the  hmpid  fluid  which  fills  all  the 
passages  of  the  internal  ear.  The  auditory  nerve 
notices  nothing  but  sound. 

Care  of  the  Ear. — The  ear  needs  little  care  ex- 
cept to  be  kept  clean ;  otherwise  it  should  be  let 
alone.  The  wax  which  lines  the  inner  passage  is 
bitter,  and  prevents  insects  from  crawling  in.*  It 
should  not  be  removed.  In  summer,  boys,  while  in 
swimming,  often  get  water  into  their  ears.  It  fre- 
quently remains  for  a  considerable  time,  and  is  very 
disagreeable.  This  difficulty  may  be  prevented  by 
stuffing  a  little  cotton  into  the  ears  before  going 
into  the  water. 

The  Sense  of  Seeing. 

Light. — It  is  now  generally  believed  that  light, 
as  well  as  sound,  is  produced  by  vibrations.  But 
while  sound  comes  from  vibrations  of  the  air,  light 
is  the  result  of  vibrations  of  a  fluid  much  thinner 
than  air,  and  which  fills  all  the  space  between  the 
earth,  the  sun,  and  the  stars.  These  vibrations 
make  no  impression  upon  any  of  the  nerves  of  the 

*  In  spite  of  all  care,  an  insect  sometimes  gets  into  the  ear,  where 
its  movements  sound  exceedingly  loud.  When  this  happens,  oil  may 
be  used  to  destroy  the  life  of  the  intruder,  and  then  the  ear  may  be 
cleansed  by  means  of  a  soft  cloth. 


128  HOW    WE  LIVE, 

body  except  the  optic  nerve  of  the  eye,  and  here  it 
gives  the  impression  which  is  called  light.* 

Need  of  Light. — The  mind  needs  to  know  the 
forms  and  positions  of  objects.  The  body,  in  travel- 
ing in  search  of  food,  must  avoid  the  abrupt  preci- 
pice, the  dangerous  pit,  the  deep  water.  It  must 
have  some  sure  guide  to  the  things  necessary  to  its 
existence.  The  mind  must  be  able  to  judge  of  dis- 
tance for  purposes  of  use  and  protection.  It  also 
has  higher  needs.  For  its  own  growth  and  happi- 
ness it  must  be  able  to  see  the  beauty  which  color 
unfolds,  and  which  is  found  in  the  shifting  scenes  of 
mountain  and  sea,  and  in  the  varying  forms  of  ani- 
mal and  vegetable  life.  All  these  come  to  the  mind 
by  means  of  light  and  through  the  eye. 

The  Eye. — The  eyes  are  spherical  bodies  about 
one  inch  in  diameter,  and  are  placed  in  bony  sockets 
in  the  front  part  of  the  skull.  On  all  sides,  except 
the  front,  they  are  protected  by  strong  bones  and 
cushions  of  soft  tissue.  The  eyelids,  with  rows  of 
eyelashes  along  their  edges,  can  close  over  the  front 
of  the  eyes,  so  as  to  protect  them  from  dust  and  in- 
sects. The  eyebrows  turn  the  sweat  on  the  fore- 
head away  from  the  eyes.  Tears  keep  the  eyes  moist, 
and  winking  spreads  the  tears  over  their  surface.f 

*  By  means  of  a  prism  it  is  sliovn  that  light  is  composed  of  many 
colors.  Differences  in  color  are  supposed  to  come  from  difference  in 
the  rapidity  of  the  vibrations  which  produce  light. 

•)•  A  tube  connects  the  tear-gland  with  the  nose,  so  that  extra  tears 
usually  flow  through  it.  In  case  of  great  grief,  or  anger,  the  tears 
overflow,  and  this  excess  of  tears  is  called  weeping.  Sometimes  the 
tube  leading  to  the  nose  gets  obstructed,  producing  what  is  termed  a 
"  weeping  eye." 


NOW   THE  MIND   GETS  IDEAS.  129 

Structure. — The  eye  has  three  coats.  The  scle- 
rotic coat,  on  the  outside,  is  strong  and  tough.  It 
serves  to  keep  the  eye  in  shape,  and  also  as  a  place 


Ofi.\ 

Fig.  31. — Horizontal  section  of  the  eyeball:  Scl,  sclerotic  coat ;  Cn,  cornea; 
Ch,  choroid ;  /r,  iris ;  Aq^  aqueous  humor ;  Cry,  crystalline  lens ; 
Vt,  vitreous  humor  ;  Rt^  retina  ;  Op,  optic  nerve. 

of  attachment  for  muscles.  This  coat  has  an  open- 
ing in  front,  in  which  a  convex  transparent  mem- 
brane called  the  cornea  is  placed,  very  much  as  a 
crystal  is  inserted  in  a  watch.  Next,  inside,  is  the 
choroid  coat,  made  of  softer  tissue,  and  containing 
the  blood-vessels  that  supply  the  eye.  The  interior 
part  of  this  coat  is  black  or  very  dark-colored.* 
The  retina,  or  inside  coat,  is  formed  by  the  spread- 

*  The  dark  interior  surface  of  the  choroid  coat  absorbs  the  light 
■which  is  not  needed  for  clearness  of  seeing.  When  this  black  coloring- 
matter  is  wanting,  as  in  the  case  of  albinos,  vision  is  defective. 


I30  HOW    WE  LIVE. 

ing  out  of  the  optic  nerve  over  the  back  part  of 
the  eye. 

The  crystalline  lens  is  a  transparent  body,  shaped 
like  a  convex  eye-glass,  only  much  thicker  in  the 
middle.  It  lies  near  the  front  of  the  eye,  encircled 
by  the  sclerotic  coat.  The  space  back  of  the  crys- 
talline lens  is  filled  with  a  transparent,  jelly-like 
substance  called  the  vitreous  humor ;  and  the  space 
between  the  crystalline  lens  and  the  cornea  is  filled 
with  a  watery  fluid  called  the  aqueous  humor.  In 
front  of  the  crystalline  lens  is  a  colored  curtain 
called  the  iris.  Through  the  iris  is  an  opening 
called  the  pupil,  through  which  light  is  admitted. 
The  muscles  of  the  iris  are  so  constructed  that  in 
a  dim  hght  they  enlarge  the  pupil  so  as  to  admit 
more  light,  and  in  strong  light  they  diminish  the 
pupil  so  that  some  of  the  light  is  shut  out.* 

Muscles  of  the  Eye. — Muscles  in  the  interior  of 
the  eye  change  the  form  and  position  of  the  crys- 
talline lens,  and  enlarge  and  diminish  the  iris  for 
the  purpose  of  adjusting  the  light.  The  motion  of 
the  whole  eye  is  controlled  by  four  straight  mus- 
cles which  move  it  up  and  down,  and  from  right 
to  left.  Besides  these,  one  muscle  goes  through  a 
pulley,  and  rolls  the  eye  around  in  its  socket.f 

*  The  effect  of  light  upon  the  iris  may  be  seen  by  observing  the 
eyes  of  a  cat.  In  a  strong  light  the  pupil  closes  so  nearly  that  it  ap- 
pears only  as  a  faint  line.  In  a  dim  light  the  pupil  enlarges  so  much 
that  the  iris  neai'ly  disappears. 

f  When  the  interior  muscles  are  too  strong,  the  eyes  are  turned 
toward  the  nose,  producing  internal  strabismus,  or  "  cross-eyes."  "When 
the  exterior  muscles  are  too  strong,  exterior  strabismus  results.  These 
difficulties  can  be  easily  remedied  by  a  skillful  surgeon. 


HOW   THE  MIND   GETS  IDEAS,  131 

Action  of  Light.  —  The  light  enters  the  eye 
through  the  cornea,  and  passes  through  the  aque- 
ous humor.  The  iris  here  steps  in  and  shuts  off  all 
light  not  needed.  The  crystalline  lens  next  receives 
the  light  that  the  iris  permits  to  pass,  and  so  adjusts 
itself  that  the  light  falls  upon  the  retina  in  just  the 
way  to  make  the  right  impression  of  form.  When 
vision  is  perfect,  an  exact  image  of  the  object  seen 
is  made  upon  the  retina.* 

Care  of  the  Eye. — The  crystalline  lens  is  some- 
times too  convex,  producing  short-sightedness. 
This  trouble  calls  for  the  use  of  concave  glasses. 
As  old  age  comes  on,  the  crystalline  lens  becomes 
flattened,  and  convex  glasses  are  needed.  When 
we  read  or  study,  the  Hght  should  be  thrown  upon 
the  book  or  object,  and  not  into  the  eyes.  A  glare 
of  hght  in  the  eyes  makes  objects  appear  dim.  On 
the  other  hand,  we  should  avoid  trying  to  read  or 
see  small  objects  in  a  dim  light.  If  the  strain  which 
such  a  practice  occasions  is  continued,  it  is  liable  to 
weaken  the  eyes  and  produce  temporary  or  per- 
manent blindness.  Cross-Hghts,  or  lights  coming 
into  a  room  at  different  angles,  are  hurtful  to  the 
eye.  As  these  lights  are  of  different  intensity,  the 
muscles  of  the  iris  become  weary  of  trying  prop- 
erly to  adjust  the  ever-changing  light. 

*  Get  from  the  butcher  the  eye  of  an  ox ;  carefully  cut  away  the 
sclerotic  coat  on  the  back  side  ;  then  darken  a  room,  except  one  ray  of 
light.  In  this  opening  place  the  eye,  as  though  looking  out.  On  the 
retina  can  then  be  seen  a  distinct  image  of  objects  outside,  but  they 
appear  upside  down.  From  the  same  eye  may  be  obtained  an  idea  of 
the  brilliancy  and  transparency  of  the  vitreous  humor. 
9 


132  HOW    WE  LIVE. 

The  Organs  of  Speech. 

The  mind  has  need  to  express  thought  as  well 
as  to  receive  it.  It  needs  not  only  to  learn  from 
the  experience  of  others,  but  also  to  give  to  others 
the  result  of  its  own  experience.  The  most  effect- 
ive means  by  which  this  interchange  of  ideas  is 
brought  about  is  the  voice  as  heard  in  speech.  Cer- 
tain combinations  of  sounds  are  called  words,  and 
words  express  ideas. 

The  Voice.  —  The  larynx  is  the  prominence 
which  lies  immediately  above  the  trachea.  The 
triangular  opening  from  the  mouth  into  the  larynx 
is  called  the  glottis.  Along  each  side  of  the  glottis 
are  thin  membranes  called  vocal  cords.  These  mem- 
branes usually  hang  loose,  but  they  can  be  stretched 
and  made  to  vibrate.  They  then  produce  sound  in 
much  the  same  way  as  it  is  produced  by  the  vibrat- 
ing strings  of  a  musical  instrument.  This  sound  is 
the  voice. 

Speech. — The  sounds  of  the  voice  will  be  higher 
or  lower  as  the  vocal  cords  are  more  or  less  tight- 
ened, and  so  vibrate  faster  or  slower.  By  slight 
changes  in  the  opening  of  the  glottis  the  sound  can 
also  be  made  to  vary  in  quality  and  quantity.  The 
voice,  coming  out  through  the  mouth,  is  shaped  into 
articulate  speech  by  the  teeth,  tongue,  palate,  roof 
of  mouth,  and  lips,  under  the  direction  of  the  mind.* 

*  Speech  is  chiefly  a  matter  of  imitation.  Children  who  are  accus- 
tomed to  hear  correct  speech  will  usually  speak  correctly.  During  the 
first  three  or  four  years  of  school-life,  distinctness  of  speech  may  be  pro- 
moted by  giving  raiher  more  than  the  usual  prominence  to  the  syllables 


HO  IV  THE  MIND  EXPRESSES  IDEAS.      133 

Care  of  the  Voice. — Scarcely  anything  is  more 
to  be  desired  than  a  pleasant  voice.  The  possessor 
of  such  a  voice  is  sure  to  be  heard  when  no  heed  is 
given  to  others,  and  his  presence  gives  pleasure 
where  that  ot  others  would  give  pain.  To  secure 
the  possession  of  these  pleasant  tones,  care  must  be 
taken  not  to  put  too  great  a  strain  upon  the  vocal 
cords  in  youth.  Screaming,  loud  wrangling,  bois- 
terous singing,  and  hallooing,  all  have  a  tendency  to 
break  or  harden  the  vocal  cords,  so  that  afterward 
they  can  make  none  but  coarse  and  harsh  tones. 
Care  must  also  be  taken  not  to  use  the  vocal  cords 
much  when  the  throat  is  sore  from  any  cause. 

Hygiene  of  the  Organs  of  Special  Sense. 

I.  When  things  taste  bad,  we  should  examine 
them  with  great  care,  and  know  that  they  are  not 
harmful  before  we  eat  them. 

II.  We  should  be  careful  not  to  injure  the  sense 
of  taste  by  the  use  of  tobacco  and  other  pungent 
substances. 

III.  Things  that  smell  bad  should  be  avoided. 

IV.  It  is  well  to  refresh  ourselves  and  to  stimu- 
late our  nerves  by  a  very  moderate  use  of  perfumery. 

V.  Keep  all  hard  instruments  out  of  the  ear-pas- 
sages. 

VI.  Do  not  sit  facing  the  light. 

VII.  Do  not  use  the  eyes  much  in  a  dim  light. 

VIII.  Do  not  try  to  study  or  look  closely  with 
cross-lights  or  other  uncertain  and  varying  lights. 

of  words.     Later  the  same  object  may  be  gained  by  short  daily  drills 
upon  the  vocal  elements  of  the  language. 


134  ^OlV   WE  LIVE. 

IX.  Do  not  attempt  to  see  much  when  the  eyes 
give  notice  of  exhaustion  by  sleepiness  or  pain. 

X.  Do  not  strain  the  vocal  cords  by  continued 
loud  and  high  tones  in  singing  or  in  speech. 

XL  Use  the  voice  gently  at  the  period  when  it 
is  "  changing,"  and  always  when  there  is  any  in- 
flammation of  the  throat 

Something  to  Find  Out. 

1.  What  part  of  the  skin  is  best  supphed  with 
sensory  nerves,  and  is  therefore  the  most  sensitive  ? 

2.  What  can  we  find  out  by  the  sense  of  touch  ? 

3.  Why  does  a  piece  of  marble  feel  cooler  than 
a  piece  of  fur  that  lies  by  its  side  ? 

4.  Does  it  ever  happen  that  the  marble  feels 
warmer  than  the  fur  under  the  same  conditions  ? 

5..  Why  can  we  not  taste  a  piece  of  marble  ? 

6.  How  can  we  tell  the  flavor  of  a  fruit  that  we 
have  heard  described  but  have  never  seen? 

7.  What  old  fable  shows  the  folly  of  deciding 
upon  the  flavor  of  grapes  that  grow  out  of  reach? 

8.  Why  can  we  not  relish  the  flavor  of  a  peach 
just  after  taking  quinine  ? 

9.  What  difference  does  the  gustatory  nerve  per- 
ceive between  the  surface  of  a  piece  of  iron  and  that 
of  a  piece  of  soft,  cotton  cloth  ? 

10.  Why  should  we  take  considerable  time  for 
each  of  our  meals  ? 

11.  Why  should  we  not  usually  spend  several 
hours  at  a  meal  ? 

12.  Why  are  roses  and  lilacs  so  frequently  plant- 
ed about  houses  ? 


HOW   THE  MIND  GETS  IDEAS. 


135 


13.  What  would  be  the  effect,  if  fragrant  flowers 
could  be  planted  around  all  homes  ? 

14.  Why  should  we  object  to  having  a  tannery 
or  a  slaughter-house  put  up  near  our  dwelling  ? 

15.  In  what  way  can  we  turn  to  profitable  ac« 
count  the  decaying  vegetable  and  animal  substances 
which  give  off  bad  odors  ? 

16.  Why  should  we  cultivate  a  liking  for  pleas- 
ant odors,  and  learn  to  discriminate  between 
them? 

1 7.  What  animals  are  noted  for  keenness  of  scent  ? 
Of  what  use  is  this  sense  to  them  ? 

18.  What  are  some  of  the  disadvantages  of  being 
deaf? 

19.  What  pleasures  of  a  high  character  do  we 
get  through  the  ear  ? 

20.  What  special  charms  has  an  early  morning 
walk  in  the  country  in  summer  ? 

21.  When  near  by,  why  is  the  shrill  whistle  of  a 
locomotive  or  the  clang  of  a  gong  disagreeable  ? 

22.  Read  from  Goldsmith's  "  Deserted  Village  " 
the  description  of  summer  evening  sounds.  What 
sounds  are  described,  and  why  do  they  all  make  so 
pleasant  an  impression  ? 

23.  What  advantage  has  the  cultivated  musician 
over  one  who  has  no  taste  for  music  ? 

24.  What  difference  in  shape  do  you  notice  be- 
tween the  pupil  of  a  cat's  eye  and  that  of  your 
own? 

25.  What  differences  do  you  notice  in  the  iris  of 
the  eyes  of  different  persons  ? 

26.  What  in  other  parts  of  the  body  corresponds 


136  //OIV    WE  LIVE. 

to  the  coloring  of  the  iris,  and  the  black  coloring- 
matter  of  the  interior  of  the  eye  ? 

27.  What  is  the  color  of  the  eyes  of  an  albino, 
and  why  is  his  sight  defective  ? 

28.  What  are  some  of  the  useful  ideas  which  we 
get  through  the  eye  ?  1 

29.  What  pleasurable  emotions  come  from  trav- 
eling among  the  mountains  ? 

30.  What  from  observing  the  sea  ?    What  from 
a  walk  in  the  garden  ? 

31.  How  does  voice  differ  from  speech  ? 

32.  What  are  some  of  the  disadvantages  of  a 
harsh  voice  ? 

33.  What  does  a  pleasant  voice  indicate  ? 

34.  Why  should  not  httle  children  be  permitted 
to  sing  "  at  the  top  of  their  voices  "  ? 

35.  What  advantage  comes  from  always  hearing 
clear  and  pleasant  tones  in  speech  ? 


CHAPTER  XI. 

STIMULANTS  AND   NARCOTICS. 

/.  Stimulants. 

Unnecessary.-^Continuous  exercise  without  in- 
termission is  impossible.  Even  the  heart,  which 
seems  always  busy,  rests  more  than  it  works.  It  re- 
poses and  feeds  between  its  beats.  Its  resting  spells 
are  short,  but  they  come  often.  They  occupy  three 
fifths  of  the  time,  so  that  in  twenty-five  hours  the 
heart  works  but  ten  and  reposes  fifteen. 

When  muscular  or  mental  exercise  is  too  violent 
or  prolonged,  fatigue  is  felt.  The  waste  of  muscu- 
lar or  brain  substance  is  greater  than  the  repair. 
Food  and  rest  relieve  the  fatigue. 

The  repairing  materials  are  supplied  by  the 
food  ;  they  are  used  during  rest. 

The  food  should  be  sufficient  but  not  excessive 
in  quantity  ;  nutritious,  easily  digestible,  and  varied 
in  quality.  The  time  devoted  to  eating  and  repose 
should  be  ample.  It  should  not  be  stinted  nor  be- 
grudged as  if  it  were  misspent. 

When  the  various  parts  of  the  body  are  in  a 
healthy  condition,  only  food  and  rest  are  required 
to  enable  them  to  exercise  their  functions  to  the  best 
advantage. 


138  HOW   WE  LIVE. 

In  disease  there  may  be  emergencies  when  stimu- 
lants are  useful  and  necessary.  Like  the  helping 
hand  extended  to  an  exhausted  swimmer,  they  may 
save  from  fatal  sinking.  Like  the  whip  which  is 
vigorously  applied  to  the  overtasked  and  straining 
street-car  horses,  when  they  falter  near  the  summit 
of  the  hill,  stimulants  may  impart  an  artificial 
strength  which  shall  be  sufficient  to  overcome  the 
difficulty.  But  stimulants  are  goads.  They  do  not 
nourish.  They  add  nothing  to  the  material  from 
which  permanent  strength  is  derived.  In  health 
they  are  useless.  The  horse  which  can  do  its  cus- 
tomary work  only  while  under  the  constant  appli- 
cation of  the  lash  is  really  disabled  by  laziness  or 
disease.  And  the  person  who  resorts  to  alcoholic 
stimulants  because  he  thinks  that  without  their  fre- 
quent goading  he  can  not  perform  the  drudgeries, 
or  even  the  ordinary  duties  of  life,  is  in  a  pitiable 
condition.     If  he  be  in  health  he  is  mistaken. 

Observation  proves  that,  in  the  long  run,  more 
and  better  mental  and  physical  work  can  be  done ; 
hunger,  fatigue,  and  long  exposure  to  extreme  cold 
or  heat  better  endured  ;  and  that  the  average  health 
approaches  more  nearly  a  perfect  standard  without 
than  with  the  habitual  use  of  stimulants. 

Injurious. — But  stimulants  are  injurious.  Like 
the  too  powerful  mainspring  in  a  delicate  watch, 
they  produce  strong  and  violent  manifestations,  but 
they  wear  out  the  works. 

The  tendency  of  alcoholic  stimulants — and  these 
are  the  only  ones  now  under  consideration — is  to 
impair  the  normal  action  of  the  various  parts  of  the 


STIMULANTS  AND  NARCOTICS.  139 

body,  and  even  to  produce  serious  organic  disease. 
How  this  is  accomplished  is  explained  in  various 
parts  of  this  book. 

One  of  the  saddest  results  of  the  use  of  these 
stimulants  is  a  diseased  craving,  which  can  be  satis- 
fied only  by  the  further  use  of  that  which  caused 
the  craving  and  which  intensifies  it. 

Daily  observation  and  abundant  testimony  prove 
that  this  acquired  appetite  may,  and  in  numberless 
instances  does,  become  almost  irresistible,  requiring 
increasing  potations  to  appease  its  insatiable  de- 
mands, and  dragging  down  its  helpless  victims, 
through  disease  and  loss  of  self-respect  and  blunted 
moral  perceptions,  and  even  crime,  to  utter  ruin. 

If  alcoholic  stimulants  are  unnecessary,  injuri- 
ous, and  dangerous,  should  they  not  be  avoided  "> 
Is  not  the  path  of  safety  the  path  of  wisdom  ?* 


2,  Narcotics. 

These  are  substances  which  first  exhilarate  and 
then  induce  drowsiness  or  stupor.  There  are  many 
of  them,  but  two  only  will  be  noticed  here :  opium 
and  tobacco. 

*  As  showing  how  the  habit  of  using  alcoholic  beverages  dimin- 
ishes the  likelihood  of  recovery  from  serious  illness,  the  following 
statement  is  of  great  value.  It  is  from  the  report  of  the  Investigation 
Committee  appointed  by  the  British  Medical  Association.  The  re- 
port was  published  in  July,  1884. 

In  1,065  cases  of  pneumonia  there  were  192  deaths. 

The  mortality  of  the  temperate  was  17  per  cent. ;  of  the  intemper- 
ate, nearly  43  per  cent. ;  while  Of  the  total  abstainers  it  was  but  ro 
per  cent. 


I40  HO IV   WE  LIVE. 

The  consumption  of  opium  and  its  various  prep- 
arations  has  greatly  increased  within  a  few  years. 
While  its  continuous  use  does  not  seem  to  shorten 
materially  the  life  of  its  devotees,  it  renders  it 
miserable.  It  enfeebles  the  intellect,  enervates  the 
bodily  powers,  and  gives  a  dull  and  vacant  appear- 
ance to  the  face.  Habitual  opium-eating  always 
weakens  and  perverts  the  moral  sense.  From  its 
firm  grasp  its  victims  seldom  escape.  Their  brief 
struggles  for  release  become  more  and  more  im- 
potent, till  finally  the  captivity  is  accepted  as  hope- 
less. Opium  should  be  taken  only  when  adminis- 
tered by  a  wise  and  prudent  physician. 

Tobacco  affects  primarily  the  nervous  system. 
It  stimulates  and  it  soothes.  It  seems  to  furnish 
great  pleasure  to  those  who  chew  or  smoke  it.  But 
it  has  its  drawbacks.  Its  habitual  use  impairs  di- 
gestion, often  causes  palpitation  of  the  heart,  trem- 
bling of  the  hands,  disturbance  of  the  delicate 
bronchial  tissue,  and  sometimes  permanent  injury 
of  the  nerves. 

Chewing  is  specially  filthy.  Smoking  is  offen- 
sive to  a  large  proportion  of  the  best  people. 

Those  who  have  abandoned  the  use  of  tobacco 
declare  that  they  have  sweeter  breath,  cleaner 
tongues,  better  digestion,  steadier  nerves,  increased 
power  of  endurance,  and  a  higher  average  of  enjoy- 
.  ment ;  and  that  the  loss  of  the  fascinating  excite- 
ment is  more  than  offset  by  freedom  from  the  result- 
ing depression. 

Should  not  a  practice,  however  popular,  which  is 
filthy,  offensive,  hurtful,  and  expensive,  be  avoided  ? 


WHAT  THE  WORDS  MEAN. 


Ab-do'men  (Latin,  abdo,  to  hide).  The  largest  cavity  of  the  body, 
situated  beneath  the  level  of  the  diaphragm,  and  containing  the 
liver,  stomach,  intestines,  etc.  ;  the  belly. 

Ab-sor'bents  (Latin,  ab  and  sorbeo,  to  suck  up).  The  vessels  which 
take  part  in  the  process  of  absorption. 

Ab-sorp'tion.  The  process  of  sucking  up  fluids  by  means  of  an 
animal  membrane. 

Ac'id  (Latin,  acidtis,  from  acere,  to  be  sour).  A  substance  usually  sour, 
sharp,  or  biting  to  the  taste. 

Ad'am's  Ap'ple.  An  angular  projection  of  cartilage  in  the  front  of 
the  neck.  It  is  particularly  prominent  in  males,  and  is  so  called 
from  a  notion  that  it  was  caused  by  the  apple  sticking  in  the  throat 
of  our  first  parent. 

Al-bi'no  (Italian,  albino,  whitish).  A  person  having  a  peculiar  white- 
ness of  the  skin  and  hair,  and  a  redness  of  the  iris  and  pupil  of  the 
eye. 

Al-bu'men  (Latin,  albus,  white).  An  organic  substance  resembling 
white  of  egg. 

Al-bu'mi-noids  (Latin,  albumen,  and  Greek,  eidos,  form).  A  class 
of  substances  resembling  albumen  ;  they  may  be  derived  from  either 
the  animal  or  the  vegetable  kingdom. 

Al'co-hol  (Arabic,  al  kohl,  a  powder  to  paint  the  eyebrows  with).  The 
intoxicating  element  of  spirituous  liquors. 

Al-i-ment'a-ry  Ca-nal'  (Latin,  alimentarius,  from  alo,  to  nourish).  A 
long  tube,  of  varying  form  and  size  in  its  different  parts,  in  which 
the  digestion  of  the  food,  or  "aliment,"  is  performed.  It  com* 
pris€s  the  mouth,  the  pharynx,  the  esophagus,  the  stomachy  and  the 
small  and  large  intestine. 


142  WHAT   THE    WORDS  MEAN. 

Al'ka-li  (Arabic,  al  kali,  the  soda-plant).  A  name  given  to  certain 
substances,  such  as  soda,  potash,  and  the  like,  which  have  the  power 
of  combining  with  acids  to  form  salts. 

A-nat'o-my  (Greek,  anatome,  cutting  up,  dissection).  The  study  of 
the  different  parts  and  the  structure  of  the  body. 

Am'y-loid  (Greek,  amulon,  fine  meal,  and  eiaos,  form).  A  substance 
similar  to  amyle,  which  is  composed  of  ten  parts  of  carbon  and 
eleven  of  hydrogen. 

A-or'ta  (Greek,  aorteomai,  to  be  lifted  up).  The  largest  artery  of  the 
body,  and  main  trunk  of  all  the  arteries.  It  arises  from  the  left 
ventricle  of  the  heart.  The  name  was  first  applied  to  the  two  large 
branches  of  the  trachea,  which  appear  to  be  lifted  up  by  the  heart. 

Ap-pend'age  (Latin,  ad,  to,  and  pendeo,  to  hang).  Something  added 
to  a  principal  or  greater  thing. 

A'que-ous  Humor  (Latin,  aqua,  water).  A  few  drops  of  watery, 
colorless  fluid  occupying  the  space  between  the  cornea  and  crystal- 
line lens. 

A-ro'ma  (Latin).     The  agreeable  odor  of  plants  or  other  substances. 

Ar-te'ri-al  Blood.  The  bright -red  blood  in  the  left  side  of  the  heart 
and  the  arteries  of  the  general  circulation. 

Ar'ter-y  (Greek,  aer,  air,  and  tereo,  to  keep).  A  vessel  conveying  the 
blood  from  the  heart  outward  to  the  organs  ;  so  called  because  the 
ancients  thought  these  vessels  contained  air. 

Ar-tic-u-la'tion  (Latin,  articulo,  to  form  a  joint).  The  movable 
union  of  bones  ;  a  joint. 

Ath-let'ic  (Greek,  athleo,  to  contend  for  a  prize).  Belonging  to 
wrestling,  boxing,  running,  and  other  manly  exercises  and  sports. 

Au'di-to-ry  Nerve  (Latin,  audio,  to  hear).  The  special  nerve  of  the 
sense  of  hearing. 

Au'ri-cle  (Latin,  auricula,  the  outer  ear).  The  smaller  and  thinner 
chamber  of  the  heart  on  each  side,  which  receives  the  blood  directly 
from  the  veins  ;  so  called  from  a  fancied  resemblance  in  shape  to  a 
dog's  ear. 

Au-to-mat'ic  (Greek,  automatos,  self-moving).  Self-acting  ;  not  de- 
pending on  the  will. 

Bi'ceps  (Latin).  A  muscle  situated  upon  the  front  part  of  the  arm 
above  the  elbow,  which  serves  to  bend  the  elbow-joint. 

Bi-cus'pid  (Latin,  bi,  two,  and  cuspis,  prominence).  The  name  of 
the  fourth  and  fifth  teeth  on  each  side  of  the  jaw  ;  possessing  two 
prominences. 


WHAT  THE    WORDS  MEAN.  143 

Bile.  The  gall,  or  peculiar  secretion  of  the  liver  ;  a  sticky,  yellowish 
fluid,  and  very  bitter  to  the  taste. 

Blonde.     Of  a  fair,  or  light,  color  or  complexion. 

Bone.  A  firm,  hard  substance,  of  a  white  or  pale-rose  color,  compos- 
ing the  skeleton  or  firmer  part  of  the  body. 

Brain.  The  mass  of  nervous  substance  contained  in  the  cavity  of  the 
skull. 

Bron'chi  (Greek,  bronchos,  the  windpipe).  The  two  larger  branches 
into  which  the  trachea  is  divided,  and  into  which  the  bronchial  tubes 
open. 

Bron'chi-al  Tubes.  The  smaller  branches  of  the  trachea  within  the 
substance  of  the  lungs,  ending  in  the  air-cells. 

Bru-nette'.     Of  a  brown  or  dark  color  or  complexion. 

Ca-Iis-then'ics  (Greek,  kalos,  beautiful,  and  sthenos,  strength).  The 
practice  of  healthful  exercise  of  the  body  and  limbs,  to  give  strength 
and  grace  of  movement. 

Cal'lus  (Latin,  calleo,  to  be  thick-skinned).  Any  excessive  hardness  ol 
the  skin,  caused  by  friction  or  pressure. 

Ca-nal'  (Latin,  canna,  a  pipe).     In  the  body,  any  tube  or  passage. 

Ca-nine'  Teeth  (Latin,  cams,^Aog).  The  pointed  teeth  situated  just 
outside  the  incisors,  one  on  each  side  in  each  jaw  ;  so  called  because 
they  are  very  prominent  in  the  dog,  as  well  as  in  other  flesh-eating 
animals. 

Cap'il-la-ries  (Latin,  capillus,  hair).  The  smallest  blood-vessels,  be- 
tween the  arteries  and  the  veins  ;  so  called  from  their  minute  or 
hair-like  size. 

Car-bon'ic  Ac'id  (Latin,  carbo,  coal).  The  gas  which  is  present  in 
the  air  expelled  from  the  lungs  ;  a  waste  product  of  the  animal 
kingdom,  and  a  food  of  the  vegetable  kingdom. 

Car'di-a  (Greek,  kardia,  heart).  The  upper  opening  of  the  stomach, 
through  which  the  food  enters  from  the  esophagus ;  so  called  be- 
cause it  is  situated  near  the  heart. 

Car'di-ac.     Pertaining  to  the  heart  or  to  the  cardia 

Car'ri-on  (Latin,  caro,  flesh).  The  dead  and  decaying  bodies  of  animals. 

Car'ti-iage  (Latin,  cartilago).  A  firm,  elastic  substance,  like  India- 
rubber,  attached  to  the  bones  in  various  parts  of  the  body,  fonning 
a  part  of  the  joints,  air-passages,  nostrils,  and  ear. 

Cav'i-ty  (Latin,  cavusy  hollow).     A  hollow,  inclosed  space. 

Ca'se-ine  (Latin,  caseus,  cheese).  The  albuminoid  substance  of  milk, 
forming  the  basis  of  cheese. 


144 


WHAT  THE    WORDS  MEAN. 


Cer-e-bel'lum  (Latin,  diminutive  of  cerebrum,  brain).  The  little 
brain,  situated  at  the  back  and  lower  part  of  the  head. 

Cer'e-brum  (Latin).  The  brain  proper,  occupying  the  entire  upper 
portion  of  the  skull.  It  is  nearly  divided  into  two  equal  parts, 
called  hemispheres,  by  a  cleft  extending  backward  from  the  front 
part  of  the  head. 

Chest.  The  upper  part  of  the  trunk  of  the  body,  inclosed  by  the 
spinal  column  behind,  the  ribs  on  the  sides,  and  the  breast-bone  in 
front. 

Cho'roid  (Greek,  chorion,  skin,  and  eidos,  like).  A  brownish-black 
membrane  forming  the  middle  coat  of  the  eye-ball. 

Chyle  (Greek,  chulos,  juice).  Chyme  changed  in  the  duodenum,  and 
turned  white  by  the  emulsion  of  fats. 

Chyme  (Greek,  chumos,  juice).  The  pulpy  liquid  formed  by  digestion 
within  the  stomach. 

Cir-cu-la'tion  (Latin,  circulus,  a  ring).  The  circuit  or  course  of  the 
blood  through  the  blood-vessels  of  the  body,  from  the  heart  to  the 
arteries,  through  the  capillaries  into  the  veins,  and  from  the  veins 
back  to  the  heart. 

Clav'i-cle  (Latin,  clavis,  a  key).  A  slender  bone,  shaped  somewhat 
like  a  key,  placed  horizontally  at  the  bottom  of  the  neck,  between 
the  top  of  the  breast-bone  and  the  point  of  the  shoulder.  The 
collar-bone. 

Col'lar-Bone.     The  clavicle. 

Con' cave  (Latin,  concavus,  hollow).  Curved  or  rounded,  like  the  in- 
side surface  of  a  hollow  globe. 

Con-ges'tion  (Latin,  con,  together,  aud  gero,  to  bring).  An  unnatural 
gathering  of  blood  in  any  part  of  the  body. 

Con-nect'ive  Tis'sue.  A  tissue  consisting  of  loose  fibrous  bundles, 
which  is  placed  between  the  muscles  and  other  parts. 

Con-sump'tion  (Latin,  consume,  to  take  entirely).  A  disease  of  the 
lungs,  attended  with  a  fever  and  cough,  and  causing  a  gradual  de- 
cay of  the  bodily  powers. 

Con-trac'tion  (Latin,  con,  together,  and  traho,  to  draw).  The  active 
shortening  of  a  muscle  or  muscular  fiber. 

Con'vex  (Latin,  conveho,  to  bring  together).  Curved  or  rounded,  like 
the  outside  of  a  globe. 

Con-vo-lu'tions  (Latin,  convolvo,  to  roll  together).  The  foldings  of 
the  external  surface  of  the  brain. 

Cor'ne-a  (Latin,  cornu,  a  horn).   The  transparent,  horn-like  substance 


WHAT   THE    WORDS  MEAN.  145 

which  covers  the  front  part  of  the  eyeball,  through  which  the  light 

passes. 
Crys'tal-line  Lens  (Latin,  crystallum,  ice).     A  transparent,  circular 

body,  rounded  on  its  front  and  back  surfaces,  situated  in  the  eye- 
ball, just  behind  the  pupil. 
Cus'pid  (Latin,  cuspis,  a  point).     A .  pointed  tooth  next  back  of  the 

incisors. 
Cu'ti-cle  (Latin,  diminutive  of  cutisy  the  skin).     The  scarf-skin  ;  also 

called  the  epidermis. 
Cu'tis  Ve'ra  (Latin).     The  true  skin,  lying  beneath  the  cuticle  ;  also 

called  the  derma. 
Dan'druff.     The  small  scales,  or  particles,  which  separate  from  the 

scarf-skin  of  the  scalp. 
De-lir'i-um  (Latin).     A  state  in  which  the  ideas  of  a  person  are  wild, 

irregular,  and  unconnected. 
Den'tine  (Latin,  dens,  a  tooth).     The  bony  or  ivory-like  part  of  the 

teeth,  lying  directly  beneath  the  enamel. 
Der'ma  (Greek,  the   skin).     The  soft,  moist,  and  thick  underlying 

layer  of  the  skin  ;  the  true  skin,  or  cutis  vera. 
Di'a-phragm  (Greek,  diaphragma,  a  partition).     The  muscular  sheet 

which  separates  the  cavity  of  the  chest  from  that  of  the  abdomen. 
Di-ges'tion  (Latin,  di,  apart,  and  gero,  to  bear).     The  preparation  of 

the  food  in  the  alimentary  canal. 
Dig'i-ti-grade  (Latin,  digitus,  finger,  and  gradi,  to  walk).     An  animal 

that  walks  or  steps  on  its  toes. 
Dis-ease'.     An  unhealthy  condition  of  some  part  of  the  body. 
Duct  (Latin,  duco,  to  lead).     A  narrow  tube,  usually  designed  to  con- 
vey away  a  secretion  from  the  gland  in  which  it  is  produced. 
Du-o-de'num  (Latin,  duodeni,  twelve  each).     The  first  division  of  the 

small  intestines,  about  twelve  finger-breadths  long. 
E-las-tic'i-ty.     The  property  of  bodies  by  which  they  recover  their 

former   figure  or  size   after  the    removal   of  outside   pressure    or 

force. 
£n-am'el.     The  dense  material  which  covers  the  crown  of  the  tooth. 
Ep-i-der'mis  (Greek,  epi,  upon,  and  derma,  skin).     The  outer  layer  of 

the  skin  ;  the  scarf-skin,  or  cuticle. 
Ep-i-glot'tis  (Greek,  epi,  upon,  and  glottis').     A  leaf-shaped  piece  of 

cartilage  which  covers  the  top  of  the  larynx  during  the  act  of  swal- 
lowing. 
E-soph'a-gus  (Greek,  oiso,  to  carry,  and  thago^  to  eat).     The  tube 


146  WHAT  THE    WORDS  MEAN. 

leading  from  the  throat  to  the  stomach,  through  which  the  food 
and  drink  pass  in  eating. 

Ex-cre'tion  (Latin,  excernoy  to  purge  out).  The  process  by  which  the 
waste  materials  of  the  body  are  removed  ;  also  the  materials  ex- 
creted. 

Ex'er-cise  (Latin,  exerceo,  to  keep  busy).  Effort  or  action  of  the  body 
for  the  sake  of  training,  or  of  keeping  its  organs  and  functions  in  a 
healthy  state. 

Ex-pan'sion  (Latin,  ex,  out  of,  and  pando,  to  open).  The  act  of  ex- 
tending or  spreading  out. 

Ex-pi-ra'tion  (Latin,  expiro,  to  breathe  out).  The  act  of  forcing  air 
out  of  the  lungs. 

Ex-ten'sor  (Latin,  ex,  out,  and  tendo,  to  stretch).  A  muscle  which 
serves  to  straighten  or  extend  a  joint. 

Eu-sta'chi-an  Tube.  A  membranous  canal,  extending  from  the  fore 
part  of  the  tympanum  of  the  ear  to  the  side  of  the  pharynx  ;  from 
Eustachi,  an  Italian  anatomist, 

Fe'mur  (Latin).     The  thigh-bone. 

Fi'ber  (Latin,  Jlbra,  a  thread).  One  of  the  string-like  portions  which 
constitute  a  part  of  the  tissues  of  plants  and  animals. 

Fi'bril  (diminutive  of  fiber).     A  very  small  branch  of  a  fiber. 

Fi'brine  (Latin, yf^nz,  a  fiber).  An  animal  matter  found  in  the  blood; 
so  called  because,  when  clotted,  it  has  a  fibrous  texture. 

Fib'u-la  (Latin,  that  which  serves  to  fasten  two  things  together).  The 
outer  and  smaller  bone  of  the  leg. 

Flex'or  (Latin,  Jlecto,  flexum,  to  bend).  A  muscle  which  serves  to 
bend  a  limb  or  joint. 

Flip'per.     The  broad  fin  of  a  fish. 

Forii-cle  (Latin,  diminutive  of  follisy  a  bag).  A  little  pouch  or  de- 
pression in  a  membrane  ;  it  has  generally  a  secretory  function. 

Func'tion  (Latin,  fimgor,  functus,  to  perform).  The  office  performed 
by  any  organ  of  the  body. 

Gan'gli-on  (Greek,  ganglion^  a  knot).  A  knot-like  swelling  in  the 
course  of  a  nerve  ;  a  smaller  nerve-center. 

Gas'tric  (Greek,  gaster,  the  stomach).     Pertaining  to  the  stomach. 

Gel'a-tine  (Latin,  gelo,  to  congeal).  An  animal  substance  which  dis- 
solves in  hot  water,  and  forms  a  jelly  on  cooling. 

Gland  (Latin,  glans,  an  acorn).  An  organ  consisting  of  follicles  and 
ducts,  with  numerous  blood-vessels  ;  it  separates  some  particular 
fluid  from  the  blood. 


IVHAT  THE    WORDS  MEAN.  147- 

Glot'tis  (Greek,  glotia,  the  tongue).  The  narrow  opening  between 
the  vocal  cords  in  the  upper  part  of  the  larynx,  by  which  it  com- 
municates  with  the  throat. 

Glu'ten  (Latin).  Literally,  glue  ;  the  gluey,  albuminous  matter  of 
wheat-flour. 

Gus'ta-to-ry  Nerve  (Latin,  gustOy  to  taste).  The  nerve  of  taste  sup- 
plying the  front  part  of  the  tongue. 

Gym-nas'tics  (Greek,  gutnnazo,  to  exercise).  The  practice  of  athletic 
exercises. 

Hic'cough.  A  spasm  of  some  of  the  muscles  used  in  breathing,  accom- 
panied by  a  shutting  of  the  glottis  and  a  sudden  sound. 

Hu'me-rus  (Latin).  The  large  bone  of  the  arm  between  the  shoulder 
and  the  elbow. 

Hu'mor  (Latin).  Moisture  :  the  humors  are  transparent  contents  oi 
the  eyeball. 

Hy'gi-ene  (Greek,  huygieia,  health).  The  art  of  preserving  health 
and  preventing  disease. 

I-de'a  (Greek,  outward  appearance).  The  complete  conception  of  an 
object. 

In-ci'sor  (Latin,  incido,  to  cut).  Applied  to  the  four  front  teeth  of 
both  jaws,  which  have  sharp,  cutting  edges. 

In-den-ta'tion  (Latin,  in,  and  dens,  a  tooth).  A  notch  in  the  margin 
of  anything. 

In-fe'ri-or  Ve'na  Ca'va  (Latin,  lower  hollow  vein).  The  chief  vein 
of  the  lower  part  of  the  body. 

In-flam-ma'tion  (Latin,  prefix  in,  and  flammo,  to  flame).  A  peculiar 
diseased  condition  of  any  part  of  an  animal  body. 

In-gre'di-ent  (Latin,  ingredi,  to  go  into).  That  which  enters  into  a 
compound  as  one  of  its  constituents. 

In-spi-ra'tion  (Latin,  in,  and  spiro,  spiratum,  to  breathe).  The  act 
of  drawing  in  the  breath. 

In-ter-cos'tal  Mus'cles  (Latin,  inter,  between,  and  casta,  a  rib). 
The  muscles  which  are  situated  between  the  ribs,  and  which  move 
the  ribs  in  respiration. 

In-tes'ti-nal  Juice.  A  sticky  secretion  produced  by  the  lining  mem- 
brane of  the  small  intestine. 

In-tes'tine  (Latin,  intus,  within).  The  part  of  the  alimentary  canal 
which  is  continuous  with  the  lower  end  of  the  stomach  ;  also  called 
the  bowels. 

I'ris  (Latin,  iris,  the  rainbow).     The  thin  muscular  ring  which  lies  be- 


148  WHAT  THE    WORDS  MEAN. 

tween  the  cornea  and  crystalline  lens,  and  which  gives  the  eye  its 

brown,  blue,  or  other  color. 
Jaun'dice  {Yrenchy  jaujte,  yellow).     A  disease  in  which  the  skin  as- 
sumes a  yellowish  color,  supposed  to  be  caused  by  an  excess  of 

bile. 
Lac'te-als  (Latin,  lac,  lactis,  milk).     The  absorbent  vessels  of  the 

small  intestines  ;  during  digestion  they  are  filled  with  chyle,  which 

has  a  milky  appearance. 
Lar'ynx  (Greek).     The  box  of  cartilage  situated  at  the  top  of  the 

windpipe,  through  which  the  air  passes  from  the  throat  into  the 

trachea  ;  the  organ  of  the  voice. 
Lens  (Latin).     Literally,  a  lentil ;    a  piece  of  transparent  glass  or 

other  substance  so  shaped  as  either  to  bring  together  or  disperse 

the  rays  of  light. 
Lig'a-ment  (Latin,  ligo,  to  bind).     A  fibrous  band  or  cord,  serving  to 

attach  two  bones  to  one  another. 
Liv'er.     The  largest  gland  in  the  body,  reddish  in  color,  situated 

mainly  on  the  right  side,  below  the  diaphragm.     From  the  venous 

blood  passing  through  it,  it  secretes  bile.     The  liver  produces  from 

the  blood  an  animal  starch. 
Lobe.     A  round,  projecting  part  of  an  organ,  as  of  the  liver,  lungs,  or 

brain. 
Loin.     That  part  of  an  animal  just  above  the  hip-bone. 
Lu'bri-cate.     To  make  smooth  or  slippery. 
Lung.     One  of  the  two  organs  of  respiration  in  an  air-breathing 

animal. 
Lymph  (Latin,  lympha,   spring-water).     The  colorless,  watery  fluid 

conveyed  by  the  lymphatic  vessels. 
Lym-phat'ic  Ves'sels.     A  set  of  very  thin,  delicate  vessels,  which 

absorb  the  lymph  from  the  tissues  of  the  body,  and  convey  it  in- 
ward toward  the  center  of  the  venous  system. 
Mac-a-ro'ni  (Greek,  fnakar,  blessed).     An  article  of  food,  composed 

chiefly  of  wheat-flour  made  into  long,  slender  tubes,  and  much  used 

in  Italy. 
Mar'row.     The  soft,  fatty  substance  contained  in  the  central  cavities 

of  the  bones  :  the  spinal  marrow,  however,  is  composed  of  nervous 

tissue. 
Mas'se-ter  (Greek,  massaomai,  to  chew).     A  strong  muscle  situated 

upon  the  side  of  the  face,  which  moves  the  lower  jaw  from  below 

upward  in  chewing. 


WHAT  THE   WORDS  MEAN.  149 

Mas-ti-ca'tion  (Latin,  mastico,  to  chew).  The  act  of  cutting  and 
grinding  the  food  to  pieces  by  means  of  the  teeth. 

Me-dul'la  Ob-lon-ga'ta  (Latin).  The  "oblong  marrow."  or  nerv- 
ous cord,  which  is  continuous  with  the  spinal  cord  within  the 
skull. 

Mem'brane  (Latin,  membrum,  a  limb  or  member).  A  thin  layer  of 
tissue  serving  to  cover  some  part  of  the  body. 

Mi'cro-scope  (Greek,  mikros,  small,  and  skopeo,  to  look  at).  An  op- 
tical instrument  which  magnifies  objects. 

Molar  (Latin,  niolay  a  mill).  The  name  applied  to  the  three  back 
teeth  of  each  side  of  the  jaw,  which  are  adapted  for  grinding  the 
food,  like  millstones. 

Mo'tor  (Latin,  moveo,  tnotum,  to  move).  Causing  motion  ;  the  name 
of  those  nerves  which  conduct  to  the  muscles  the  stimulus  which 
causes  them  to  contract. 

Mu'cous  Mem'brane.  The  thin  layer  of  tissue  which  covers  those 
internal  cavities  or  passages  which  communicate  with  the  external 
air. 

Mu'cus  (Latin).  The  sticky  fluid  which  is  secreted  by  mucous  mem- 
branes,  and  which  serves  to  keep  them  in  a  moist  condition. 

Mu-ri-at'ic  Ac'id.  An  acid  consisting  of  one  part  of  hydrogen  and 
one  of  chlorine. 

Mus'cles  (Latin,  musculus^  a  little  mouse).  A  band  of  fibers  acting 
as  an  organ  of  motion  in  animal  bodies.  The  voluntary  muscles 
act  in  obedience  to  the  will,  and  contract  suddenly  ;  the  involun- 
tary muscles  do  not  obey  the  will,  and  contract  slowly. 

Nar-cot'ic  (Greek,  narkaoy  to  benumb).  A  medicine  which,  in  poi- 
sonous doses,  produces  stupor,  convulsions,  and  sometimes  death. 

Na'sal  (Latm,  nasus,  the  nose).  Pertaining  to  the  nose  ;  the  nasal 
cavities  contain  the  special  nerve  of  smell. 

Nerve  (Greek,  neuron^  a  cord  or  string).  A  glistening,  white  cord, 
shaped  like  a  tube,  and  connecting  the  brain  or  spinal  cord  with 
some  other  organ  of  the  body.  The  nerves  are  the  telegraph-wires 
of  the  body. 

Nerve-Fi'ber.  A  very  slender  thread  of  nervous  tissue  found  in  the 
nerves  ;  it  is  of  a  white  color. 

Nos'tril  (Anglo-Saxon,  nosu,  nose,  and  thyrl,  a  hole).  One  of  the 
two  outer  openings  of  the  nose. 

Nurt'ure.  To  train  up  with  care  ;  the  food  and  attention  necessary 
to  such  training. 


I50  WHAT   THE    WORDS  MEAN. 

Nu-tri'tion  (Latin,  nuUio,  to  nourish).  The  processes  by  which  the 
nourishment  of  the  body  is  accomplished. 

01-fac'to-ry  (Latin,  olfacio,  to  smell).  Pertaining  to  the  sense  of 
smell. 

O'pi-um.  A  narcotic  drug  obtained  fiom  the  juice  of  the  white 
poppy. 

Op'tic  (Greek,  opto^  to  see).     Pertaining  to  the  sense  of  sight. 

Or'gan  (Greek,  organon,  an  instrument).  Any  part  of  the  body  which 
is  adapted  to  perform  a  particular  service,  such  as  the  heart,  the 
stomach,  the  brain. 

Ox'y-gen  (Greek,  oxus,  sharp,  and  genein,  to  bring  forth).  A  gas 
forming  one  fifth  part,  by  bulk,  of  the  atmosphere,  and  essential  to 
respiration. 

Pal'ate  (Latin,  palatum,  the  palate).  The  roof  of  the  mouth,  con- 
sisting of  the  hard  and  soft  palate. 

Pan'cre-as  (Greek,  pas,  pantos,  all,  and  kreas,  flesh).  A  long,  flat 
gland  placed  behind  the  stomach;  in  the  lower  animals  this  organ  is 
called  the  siveet-bread. 

Pan-cre-at'ic  Juice.     The  secretion  produced  by  the  pancreas. 

Pa-pil'lae  (Latin,  plural  oi papilla).  The  minute  elevations  in  which 
terminate  the  fibers  of  the  nerves  of  touch  and  taste. 

Pa-ral'y-sis  (Greek,  parahw,  to  loosen).  A  disease  of  the  nervous 
system  marked  by  the  loss  of  sensation,  or  voluntary  motion,  or 
both  ;  palsy. 

Pa-tel'la  (Latin,  diminutive  oi  patina,  a  pan).     The  knee-pan. 

Pel'vis  (Latin,  a  basin).  The  bony  cavity  at  the  lower  part  of  the 
trunk  ;  the  hip-bone. 

Per-i-car'di-um  (Greek,  peri,  about,  and  kardia,  heart).  The  sac  in- 
closing the  heart. 

Per-i-os'te-um  (Greek,  pe7i,  around,  and  osteon,  a  bone).  A  fibrous 
membrane  surrounding  the  bones. 

Per-spi-ra'tion  {I^^XXvl,  perspiro,  to  breathe  through).  The  sweat,  or 
watery  fluid  poured  out  from  the  skin  ;  when  visible,  it  is  called 
sensible  perspiration  ;  when  invisible,  insensible  perspiration. 

Phar'ynx  (Greek,  pharunx,  the  throat).  The  muscular  passage  lead- 
ing from  the  back  part  of  the  mouth  to  the  esophagus. 

Phys-i-ol'o-gy  (Greek,  phusis,  nature,  and  logos,  a  discourse).  The 
science  of  the  functions  of  living,  organized  beings ;  the  study  of 
the  natural  actions  of  the  living  body. 

Pig'ment  (Latin, /m^<?,  to  paint).     Coloring-matter. 


WHAT  THE    WORDS  MEAN.  151 

Plant'i-grade  (Latin, //(2«/«,  the  sole  of  the  foot,  and  gradt,  to  walk). 

An  animal  that  walks  on  the  sole  of  the  foot,  as  the  bear. 
Pleu'ra  (Greek,  a  rib).    A  membrane  covering  the  lung  and  lining  the 

chest.     There  is  one  for  each  lung. 
Pneu-mo'nia  (Greek,  pneuma,  air,  zwdpneo,  to  breathe).     An  inflam- 
mation affecting  the  air-cells  of  the  lungs. 
Por'tal  Vein  (Latin,  porta,  a  gateway).     The  venous  trunk  formed 

by  the  union  of  all  the  veins  coming  from  the  intestine.    It  conveys 

the  blood  to  the  liver. 
Proc'ess  (Latin,  procedo,  processus,  to  proceed,  to  go  forth).     Any 

projection  from  a  surface.     Also,  a  method  of  doing  anything. 
Pro'te-id  {Gr tok,  protos,  first,  and  eidos,  form).     An  element  allied  to 

nitrogen  ;  a  substance  containing  such  elements  ;  an  albuminoid. 
Pul'mo-na-ry  {^z.\vi\,  pulmo, pulmonis,  the  lungs).     Pertaining  to  the 

lungs. 
Pulse  (LoXiw,  pello,  pulstwt,  to  beat).    The  striking  of  an  artery  against 

the  finger,  occasioned  by  the  contraction  of  the  heart,  commonly 

felt  at  the  wrist. 
Pun'gent  (Latin,  pungo,  to  prick).     Sharply  painful  or  biting. 
Pu'pil  {Laim, piipi lid).    The  central,  round  opening  in  the  iris,  through 

which  light  passes  into  the  depths  of  the  eye. 
Py-lo'rus  (Greek,  puloros,  a  gate-keeper).     The  lower  opening  of  the 

stomach,  through  which  the  food  passes  into  the  intestine  ;  so  called 

on  account  of  a  circular  band  of  muscular  fibers  by  which  the  passage 

is  guarded. 
Qui'nine  (Spanish,  qiiina,  Peruvian  bark).     An  extract  of  Peruvian 

bark  used  to  cure  fever,  and  give  vigor  to  the  system. 
Ra'di-us  (Latin,  a  spoke  of  a  wheel).      The  bone  on  the  thumb-side 
of  the  fore-arm. 
Re'flex  Ac'tion.     An  involuntary  action  of  the  nervous  system,  by 

which  an  external  impression  conducted  by  a  sensory  nerve  is  re- 
flected, or  changed  into  a  motor  impulse. 
Res-pi-ra'tion  (Latin,  re,  denoting  repetition,  and  spiro,  to  breathe). 

The  function  of  breathing,  comprising  two  acts  :    inspiration,  or 

breathing  in,  and  expiration,  or  breathing  out. 
Ret'i-na  (hat'in,  rete,  a  net).    The  membranous  expansion  of  the  optic 

nerve  in  the  interior  of  the  eyeball,  which  receives  the  impressions 

resulting  in  the  sense  of  vision. 
Rib.    One  of  the  long  bones  inclosing  the  cavity  of  the  chest.    In  man 

there  are  twelve  on  each  side.    The  upper  seven  are  called  true  ribs: 


152  WHAT  THE    WORDS  MEAN. 

the  other  five  are  the  false  fibs,  of  which  the  last  two  are  called 

floating  ribs. 
Sa-li'va  (Latin).     The  moisture  or  fluids  of  the  mouth,  secreted  by 

the  salivary  glands. 
Sal'i-va-ry  Gland.     A  gland  which  produces  saliva. 
Sar-to'ri-us  (Latin,  sartor,  a  tailor).     The  muscle  which  throws  one 

leg  across  the  other. 
Scalp  (Latin,  scalpo,  to  cut).    The  part  of  the  skin  of  the  head  usually 

covered  with  hair.     It  is  the  part  cut  off  by  Indian  warriors  as  a 

token  of  victory  over  an  enemy. 
Scap'u-la.     The  shoulder-blade. 

Scarf-Skin.     The  outer  layer  of  the  skin  ;  the  cuticle,  or  epidermis. 
Scle-rot'ic  (Greek,  skleros,  hard).     The  tough,  fibrous  outer  coat  of 

the  eyeball. 
Se-ba'ce-ous  (Latin,  sebum,  fat).     Resembling  fat ;  the  name  of  the 

oily  secretion  by  which  the  skin  is  kept  flexible  and  soft. 
Se-cre'tion  (Latin,  secerno,  secretum,  to  separate).     The  process  of 

separating  from  the  blood  some  important  fluid  ;  the  fluid  is  also 

called  a  secretion. 
Sen-sa'tion  (Latin,  sensus,  sense).     The  conscious  perception  of  an 

external   impression   by   the  nervous  system  ;    a  function  of  the 

brain. 
Sen'so-ry  Nerve  (Latin,  sentio,  to  perceive).     A  nerve  of  sense. 
Se'rum  (Latin,  whey,  buttermilk).      The   clear,  watery  fluid  which 

separates  from  the  clot  of  the  blood.     It  contains,  besides  water, 

albumen  and  mineral  substances. 
Shaft.     A  long,  slender  body,  like  a  stem  or  stalk. 
Shoulder-Blade.     The  flat,  triangular  bone  of  the   shoulder  ;   the 

scapula. 
Skel'e-ton  (Greek,  a  dried  body).    The  bony  frame-work  of  an  animal, 

the  different  parts  of  which  are  kept  in  their  proper  relative  posi- 
tions. 
Skull  (a  shell  or  bone).     The  bony  case  which  incloses  the  brain. 
Sock'et  (Latin,  soccus,  a  kind  of  low-heeled  shoe).     An  opening  into 

which  anything  is  fitted. 
Spasm  (Greek,  spasmos,  convulsion).     A  sudden,  violent,  and  invol- 
untary contraction  of  one  or  more  muscles  or  muscular  fibers. 
Spe'cial  Sense.     A  sense  by  which  we  receive  particular  sensations, 

diff'ering  from  those  of  general  sensibility  ;  such  as  those  of  sight, 

hearing,  taste,  and  smell. 


WHAT  THE    WORDS  MEAN. 


153 


Spe-cif'ic  Grav'i-ty.  The  ratio  of  the  weight  of  a  body  to  the  weight 
of  an  equal  bulk  of  some  other  body,  usually  water,  taken  as  the 
standard. 

Spher'i-cal  (Latin,  spkem,  a  globe).     Having  the  form  of  a  sphere. 

Spi'nal  Corumn.  The  connected  vertebrae  of  the  back  ;  the  back- 
bone ;  the  spine. 

Spi'nal  Cord.  A  cylinder-shaped  mass  of  nervous  matter  situated  in 
the  cavity  of  the  spinal  column. 

Spine  (Latin,  spina,  a  thorn).     A  projecting  point  or  ridge  of  bone. 

Spleen.  An  organ  largely  made  up  of  small  vessels,  and  situated 
within  the  abdomen,  near  the  left  extremity  of  the  stomach. 

Ster'num  (Greek,  sternon^  the  breast).  A  flat,  rectangular  bone,  ex- 
tending vertically  along  the  middle  of  the  chest,  to  which  the  seven 
upper  ribs  are  attached. 

Stim'u-lant  (Latin,  stimulo,  to  prick  or  goad  on).  An  agent  which 
causes  an  increase  of  vital  activity  in  the  body  or  any  of  its  parts. 

Stri'a-ted  (Latin,  sbio^  to  furnish  with  channels).  Marked  with  fine 
parallel  lines. 

Sub-cla'vi-an  Vein  (Latin,  sub,  under,  and  clavis,  a  key).  The  great 
vein  bringing  back  the  blood  from  the  arm  and  side  of  the  head  ;  so 
called  because  it  is  situated  underneath  the  clavicle,  or  collar-bone. 

Su-pe'ri-or  Ve'na  Ca'va  (Latin,  upper  hollow  vein).  The  great  vein 
of  the  upper  part  of  the  body, 

Sur'ger-y.  That  branch  of  medical  science  which  treats  of  manual 
operations  for  the  healing  of  diseases  or  bodily  injuries. 

Sut'ure  (Latin,  suo,  to  sew  or  stitch).  The  seam  or  joint  which  unites 
the  bones  of  the  skull. 

Sym-pa-thet'ic  Sys'tem  of  Nerves.  A  double  chain  of  nervous 
ganglions  connected  together  by  numerous  small  nerves,  situated 
chiefly  in  front  of  and  on  each  side  of  the  spinal  column. 

Symp'tom  (Greek,  sum,  with,  and  pipto,  to  fall).  A  sign  or  token  of 
disease. 

Sys-tem'ic.     Belonging  to  the  system,  or  body,  as  a  whole. 

Tar'tar.  A  hard  crust  which  forms  on  the  teeth,  and  is  composed  of 
salivary  mucus,  animal  matter,  and  a  compound  of  lime. 

Tem'ple  (Latin,  tevipus,  time,  and  tempora,  the  temples).  The  part 
of  the  head  between  the  ear  and  the  forehead  ;  so  called  because 
the  hair  begins  to  turn  white  with  age  in  that  portion  of  the  scalp. 

Ten'don  (Latin,  tendo,  to  stretch).  The  white,  fibrous  cord  or  band 
by  which  a  muscle  is  attached  to  a  bone  ;  a  sinew. 


154  WHAT  THE    WORDS  MEAN. 

Text'ure  (Latin,  texo,  to  weave).     The  particular  arrangement  of  tis- 
sues that  form  an  organ. 
Tho-rac'ic  Duct  (Greek,  thorax,  the  chest).     A  narrow  tube  running 

from  below  upward  within  the  back  part  of  the  chest,  which  is  the 

main  trunk  of  the  lymphatic  vessels. 
Tho'rax  (Greek,  thorax,  a  breast-plate).     The  upper  cavity  of  the 

trunk  of  the  body,  containing  the  lungs,  heart,  etc.  ;  the  chest. 
Tib'i-a.     The  principal  bone  of  the  leg  below  the  knee. 
Tis'sue.    Any  substance  or  texture  in  the  body  formed  of  various  ele- 
ments, such  as  cells,  fibers,  blood-vessels,  etc.,  interwoven  with  each 

other. 
To-bac'co    (Indian,   tabaco,  the  tube  or  pipe  in  which  the  Indians 

smoked  the  plant).     A  plant  used  for  smoking  and  chewing  and  in 

snuff.     It  has  a  strong  smell  and  a  pungent  taste. 
Tra'che-a  (Greek,  trachus,  rough).     The  windpipe,  or  the  largest  of 

the  air-passages  ;    composed  in  part  of  rings  of  cartilage,  which 

render  its  surface  rough  and  uneven. 
Trans-par'ent  (Latin,  trans,  through,  zxid^pareo,  to  appear).     Capable 

of  allowing  light  to  pass  through.     Transparent  bodies  can  be  seen 

through. 
Tri'ceps    (Latin,  tria,  three,  and  caput,  head).      The  large  muscle 

which  straightens  the  arm,  or  that  which  extends  the  leg. 
True  Skin.     The  inner  layer  of  the  skin  ;  the  cutis  vera,  or  derma. 
Trunk.     The  body,  apart  from  the  limbs. 
Tym'pa-num  (Greek,  tumpanon,  a  drum).     The  cavity  of  the  middle 

ear,  resembling  a  drum  in  being  closed  by  two  membranes,  and  in 

having  communication  with  the  atmosphere. 
Ul'na  (Latin,  the  elbow).     The  bone  of  the  fore-arm  on  the  little- 
finger  side. 

Var'i-cose  (Latin,  vaiix,  a  dilated  vein).     Unnaturally  enlarged — ap- 
plied only  to  veins. 
Vein.     A  vessel  serving  to  convey  the  blood  from  the  various  organs 

inward  to  the  heart. 
Ve'nous  (Latin,  vena,  a  vein).     Pertaining  to,  or  contained  within,  a 

vein. 
Ven-ti-la'tion  (Latin,  ventus,  wind).     The  introduction  of  fresh  air 

into  a  room  or  building  in  such  a  manner  as  to  keep  the  air  within 

it  in  a  pure  condition. 
Ven'tri-cle  (Latin,  ventriculus,   a  little  stomach).     The  larger  and 

thicker  chamber  of  the  heart,  on  each  side,  which  receives  the 


WHAT   THE    WORDS  MEAN.  155 

blood  from  the  corresponding  auricle,  and  discharges  it  into  the 

artery. 
Ver'te-bra  (Latin,   vertebra,  a  joint).      One    of  twenty-six    separate 

bones,  called  vertebrae,  firmly  jointed  together  to  form  the  spinal 

column, 
Ver'te-brate.     Having  a  backbone  formed  of  vertebrce. 
Vi-bra'tion  (Latin,  vibro,  to  move  to  and  fro).     Quick  motion  to  and 

fro. 
Vi-tal'i-ty  (Latm,  vita^  life).     The  state  or  quality  of  being  full  of 

life. 
Vit're-ous  (Latin,  vitrum,  glass).     Having  the  nature  of  glass. 
Vo'cal  Cords  (Latin,  vox,  vocis,  the  voice).     Two  elastic  bands  or 

ridges  situated  in  the  larynx  ;  they  are  the  essential  parts  of  the 

organs  of  the  voice.     Their  vibrations,  communicated  to  the  air, 

produce  the  sound  of  the  voice. 
Vol'un-ta-ry  (Latin,  voluntas, -wiW).     Under  control  or  direction  of 

the  will. 


TOPICAL  ANALYSIS. 


CHAPTER   I.— The  Body  and  its  Parts. 


Why  we  should 
Study        our  •{ 
Bodies. 


About  Parts  of 
the  Body. 


1.  The  head,  neck,  trunk,  and  limbs  seen. 

2.  The  internal  organs  not  seen. 

3.  To  avoid  injury  of  outward  parts. 

4.  To  care  for  organs  within  the  body. 

5.  To  secure  health. 

6.  To  improve  looks, 

l^  7.  To  increase  usefulness. 

1.  The  arms. 

2.  The  legs. 

3.  The  joints :  ball-and-socket — ^hinge—compound 

4.  Parts  in  pairs. 

5.  Bodies  of  other  animals. 

6.  Uses  of  parts  of  the  body. 

7.  Intelligent  care  of  the  body. 

Something  to  find  out. 


TOPICAL  ANALYSIS. 


157 


CHAPTER  II. — Eating,  and  what  comes  of  it. 


Why  we  Eat. 


What  we  Eat. 


How  we  Eat. 


How  we  Swal- 
low. 


1.  The  body  always  wearing  out. 

2.  It  needs  repair. 

3.  We  eat  to  live. 

4.  We  eat  to  do  the  work  we  have  to  do. 

1.  Different  elements  needed. 

2.  Food  related  to  the  industries. 

3.  Food  related  to  geography, 
Proteids  :  gluten  — albumen  — 

fibrine — caseine — gelatine. 
Amyloids  :     starch  —  sugar  — 

gums. 
Fats  :    animal    and    vegetable 

oils. 
Minerals  :   lime — soda — potash 
— iron — salt — water. 
Special  foods  :  vegetables — meats — fruits. 
Value  of  different  foods. 
Ways  of  cooking. 
Mixed  foods  necessaiy. 


4,  Kinds  of  food. 


1.  Mastication. 

2.  The  teeth  :  structure — names — uses. 

3.  Care  of  the  teeth:  necessity — implements. 

1.  How  saliva  flows — exciting  causes. 

2.  Amount  of  saliva. 

3.  How  saliva  is  wasted. 

4.  Tobacco:  wastes  saliva — vitiates  saliva — defiles 

the  breath. 
_  5.  The  esophagus  :  structure — action. 

Hygiene  of  mastication. 
Something  to  find  out. 


TOPICAL  ANALYSIS, 


CHAPTER   III.— How  Digestion  goes  on. 


Stomach  Diges- 
tion, 


Intestinal 
gestion. 


Di. 


1.  Structure  of  stomach. 

2.  Muscular  action. 

3.  The  gastric  juice. 

4.  The  absorbents, 

5.  Starchy  foods  changed  to  sugar  by  action  of 

saliva. 

6.  Proteids  dissolved  by  gastric  juice. 

7.  Chyme. 

8.  Character  and  amount  of  drink, 
g.  Alcohol  in  the  stomach : 

1.  Stimulates  action. 

2.  Hardens  mucous  coat. 

3.  Continued  use  inflames. 

4.  Produces  abnormal  cravings. 
[Q.  Care  of  the  stomach  : 

1.  Food  properly  prepared. 

2.  Taken  in  proper  quantities. 

3.  Taken  at  proper  times. 


-juices — action. 


1.  The  intestines:  structure- 

2.  The  duodenum. 

3.  The  pancreas  :  pancreatic  juice — uses, 

4.  The  liver :  bile — nature — uses. 

5.  Alcohol  in  the  liver: 

1.  Stimulates  action. 

2.  Hardens  tissue. 

3.  Continued  use  inflames. 

6.  The  absorbents  :  portal  vein — liver. 

7.  The  lacteals  :  chyle — the  thoracic  duct. 

8.  Summary  of  changes  : 

1.  Food  masticated  and  mixed  with  saliva. 

2.  Starch  reduced  by  saliva  and  by  action  of 

pancreatic  juice. 

3.  Proteids  reduced  by  gastric  juice. 

4.  Fats  reduced  by  pancreatic  juice  and  bile, 

5.  Acids  neutralized  by  the  alkali  of  the  bile. 

Hygiene  of  digestion. 
Something  to  Jind  out. 


TOPICAL  ANALYSIS, 


159 


CHAPTER  IV.— How  the  Blood  gets  purified. 


Mox'iment  of  the 
hlood. 


Breathing. 


Alcohol  in 
Lungs, 


Tobacco   in   the 
Lungs. 


1.  The  heart :  shape — position — covering. 

2.  The  plan  of  the  heart  : 

1.  The  pulmonary  heart. 

2.  The  systemic  heart. 

3.  The  auricles,  ventricles,  and  valves. 

3.  The  pulmonary  artery. 

4.  Pulmonary  action  : 

1.  From  vein  to  right  auricle. 

2.  From  auricle  to  right  ventricle. 

3.  From  ventricle  to  pulmonary  artery. 

1.  The  lungs  :  elastic  tissue — the  lobes — the  pleura. 

1.  Air-spaces:    air-cells  —  bronchial   tubes — ■ 

trachea — laiynx — glottis. 

2.  Blood-flow  :    around    air-cells  —  return    in 

pulmonary  veins. 

2.  The  chest  varies  in  capacity : 

1.  By  action  of  intercostal  muscles. 

2.  Movement  of  ribs  and  diaphragm. 

3.  Forces  in  breathing : 

1.  The  pressure  of  the  air. 

2.  The  elastic  force  of  the  lungs. 

4.  Action  in  the  lungs  : 

1.  Oxygen  passes  from  air-cells  into  the  blood, 

2.  Impure  matter  from  blood  passes  into  the 

air-cells. 


r  I.  Effort  to  expel  alcohol  with  the  breath, 

the  J  2.  Enfeebles  the  lungs. 

j  3,  Induces  disease. 

y  4.  The  blood  imperfectly  purified. 

1.  Tobacco-fumes  drawn  into  the  lungs. 

2.  Retards  lung-action. 

3.  Produces  languor  and  stupidity." 

4.  Retards  bodily  growth, 

5.  Enfeebles  the  mind. 


The  Need  of  Pure  Air,  Ventilation. 

Hygiene  of  respiration. 
Something  to  find  out. 


i6o 


TOPICAL  ANALYSIS, 


CHAPTER  v.— How  the  Blood  nurtures  the  Body. 


Waste  and  Re- 
pair. 

Channels  of  Cir- 
culation. 


j  I.  Action  wears  out  tissue. 

(  2.  The  blood  the  agent  of  repair. 


Action    in 
Heart. 


Action    in 
Arteries. 


the 


the 


Action    in     the 
Capillaries. 


Action    in 
Veins. 


Alcohol  in 
Blood, 


the 


the 


1.  The  arteries  :  structure — the  aorta — branches^ 

2.  The  capillaries  :  size — extent. 

3.  The  veins;  structure — termination. 

1.  From  pulmonary  vein  to  left  auricle. 

2.  From  auricle  to  left  ventricle. 

3.  From  ventricle  to  aorta. 

1.  Place  of  the  arteries. 

2.  Jets  of  blood  with  each  heart-beat. 

3.  Elasticity  of  the  walls  of  the  arteries. 

4.  The  pulse,  and  what  it  indicates. 

1.  Oxygen  bums  living  tissue. 

2.  The  burning  causes  heat  and  motion. 

3.  Worn-out  particles  are  removed. 

4.  New  particles  are  deposited. 

5.  The  color  of  the  blood  is  changed. 

1.  The  current  flows  evenly. 

2.  The  valves  open  toward  the  heart. 

3.  Muscular  action  assists  the  blood-tlow. 

4.  Varicose  veins. 

'  r.  Does  not  become  a  part  of  the  blood. 

2.  Causes  red-blood  corpuscles  to  shrink. 

3.  Deprives  the  blood  of  oxygen. 

4.  Interrupts  combustion  and  repair. 

5.  Changes  muscles  of  the  heart  into  fat 
^  6.  Gorges  minute  arteries  with  blood. 


Hygiene  of  the  circulation. 
Something  to  find  out. 


TOPICAL  ANALYSIS, 


i6i 


Motion 
sary. 


CHAPTER  VI.— How  the  Body  moves. 

ces-  (  I.  The  motion  of  the  body  and  its  parts  indicates  life. 

t  2. 


The  Muscles. 


Muscular 
Hon. 


Ac 


Care      of      the 
Muscles. 


Exercise. 


Want  of  motion  is  the  sign  of  death. 

{1.  The  muscles  produce  motion  and  give  beauty  to 
the  form. 
2.  General    structure  :     connective    tissue  —  swell 
muscles — hollow  muscles — tendons — ligaments. 

{r.  Contraction  and  expansion. 
2.  Voluntary  and  involuntary  action. 
3.  Flexors  and  extensors. 

f  I.  Repair  of  muscles  r 

1.  The  blood  supplies  nourishment. 

2.  Muscles  most  exercised  receive  most  nour- 
ishment. 

2.  Exercise  of  muscles:  work — games — calisthenics, 

3.  Rest  of  muscles :  after  exercise — after  injury. 

4.  Proper  position  :  in  sitting — in  standing. 

5.  Dress  must  leave  the  muscles  free. 

6.  Alcohol  changes  muscular  fiber  to  fat. 

7.  Agreeable  occupation  lightens  labor. 

Exercise  should  be  for  health. 
The  body  should  serve  the  mind. 
Muscular  development  not  for  display. 
Muscles  should  not  monopolize  energies. 

Hygiene  of  the  muscles. 
Something  to  find  out. 


l62 


TOPICAL  ANALYSIS. 


CHAPTER  VII.— How  the  Body  is  able  to  stand. 


Ihe  Bones, 


The  Need  of  a  \  x.  Ho  stand  erect. 
Bodily  Frame.  \  2.  To  keep  the  body  in  proper  form. 

1.  Uses  of  the  bones  : 

1.  To  give  shape  to  the  body. 

2.  To  protect  delicate  organs. 

3.  To  afford  attachment  for  muscles. 

2.  Forms  of  the  bones. 

3.  Structure  of  the  bones. 

4.  Materials :  animal  matter — mineral  matter. 

5.  Growth  and  repair. 

f  I.  Bones  of  the  head  :  skull — sutures — face. 
2.  Bones  of  the    trunk  :    pelvis — spinal   column — 
ribs  —  breastbone  —  shoulder-blade — col- 
lar-bone. 
\  3.  Bones  of  the  arm :  humerus — ulna  and  radius — 
the  wrist-bones — the  hand. 
Bones  of  the  legs  :    femur — patella — tibia  and 
fibula — ankle — foot — arch  of  the  foot. 
5.  Bony  cavities :  skull — chest — pelvis. 

How  produced. 

~~ow  shocks  are  distributed. 


Distribution  of 
the  Bones. 


Bodily      Move- 
ments. 


(  I.  H 
^2.  H 


Care     of 
Bones, 


the 


Proper  food. 

Suitable  exercise. 

Moderate  exercise  in  childhood. 

Proper  positions. 

Easy  clothing. 

Shoes  of  proper  form  and  materiaL 

Rest  after  injury. 

Hygiene  of  the  bones. 
Something  to  find  out. 


TOPICAL  ANALYSIS. 


163 


CHAPTER  VIII.— How  the  Body  is  covered. 


Uses  of  Cover-  C  i. 
ing.  \  2. 


Structure  of  the 
Skin. 


Function  of  the 
Skin. 


Care  of  the  Skin. 


V- 


The  Hair. 


Clothing. 


Protects  internal  organs. 
Performs  important  functions. 

Structure  varies  :  callus — corns — nails — ^hair. 
Layers  of  the  skin  : 

1.  The  scarf-skin  :  dandruff — pigment- cells- 

complexion. 

2.  The  true  skin  :  papillae — hair-follicles. 
How  the  skin  is  kept  soft :  oil-tubes — sebaceous 

glands. 

Casting  out  waste  :  the  sweat-glands — the  kid- 
neys. 

Regulating  heat  :  sensible  and  insensible  perspi- 
ration. 

Plow  the  skin  absorbs. 


1.  Cleanliness  of  the  skin  :  necessity — ^bathing. 

2.  Tempei-ature  of   the  skin:    clothing  —  ai'tificial 

heat. 

1.  Uses  of  the  hair : 

1.  Protects  from  extreme  heat  and  cold. 

2.  Breaks  the  force  of  blows. 

3.  Shields  organs  of  sense  from  injury. 

2.  Structure  of  hair  :  the  pith — the  shaft — the  root. 

3.  Health  of  the  hair  : 

1.  Dependent  on  general  health  of  the  body. 

2.  Necessity  of  cleanliness. 

3.  Grayness  and  loss  of  hair. 

4.  Effect  of  emotion. 

1.  Clothing  protects  and  adorns. 

2.  It  should  be  sufficient  in  quantity. 

3.  It  should  be  suited  to  circumstances. 

4.  It  should  be  clean  and  dry. 
^  5.  It  should  be  easy. 

Hygiene  of  the  skin. 
Something  to  find  out. 


II 


164 


TOPICAL  ANALYSIS, 


CHAPTER   IX. — How  Bodily  Motion  is  directed 


Direction  neces- 
sary. 


Distribution  of 

Nerves. 


Nerve-Matter. 


Nerve-Centers. 


Nerve-Function. 


Nerve-Action. 


Care      of 
Nerves. 


the 


Effect  of  Alco- 
hol. 


Effect  of  Tobac- 
co. 


1.  To  produce  harmony  of  action. 

2.  To  nurture  the  body. 
[  3.  To  execute  plans. 

r  I.  Resemblance  to  blood-vessels.  ' 

J   2.  Extending  from  nerve-centers. 
I   3.  Reaching  every  part  of  the  body. 
(^  4.  In  double  sets. 

^   I.  Gray  matter :  cells. 
\  2.  White  matter :  threads. 

1.  The    brain  :    cerebrum  —  cerebellum  —  convolu- 

tions —  double  structure  —  twelve   pairs 
cranial  nerves. 

2.  The  spinal  cord  :  the  medulla  oblongata — thirty- 

one  pairs  spinal  nerves. 

3.  The  ganglions:  general — sympathetic. 

1.  Sensory  nerves  conveying  sensations. 

2.  Motor  nerves  controlling  motion. 

r  I.  Direct  from  brain. 
J   2.  Reflex  from  spinal  cord, 
1   3.  Sympathetic  from  sympathetic  ganglions. 

[  4.  Habit  and  training. 

f  I.  Exercise  of  the  nerves. 
\   2.  Rest  of  the  nerves  :  diversion — sleep. 
(^  3.  Effect  of  emotion  :  joy — grief. 

'  I.  Absorbs  moisture  from  nerve-tissue. 

2.  Diminishes  nerve-action. 

3.  Gorges  the  small  arteries  with  blood. 

4.  Weakens  the  heart-action. 

5.  Leaves  muscles  without  control. 

6.  Deranges  the  vital  organs. 

7.  Paralyzes  cerebral  action. 
Debases  the  higher  nature. 
Produces  delirium. 

1.  Diminishes  nervous  action. 

2.  Diminishes  action  of  the  heart. 

3.  Evil  effects  transmitted  to  children. 

Hygiene  of  the  netves. 
Something  to  find  out. 


19. 


TOPICAL  ANALYSIS. 


165 


CHAPTER    X.  — How   the    Mind    gets    Ideas   and    expresses 

THEM. 

Use  of  the  Spe-  j  I.  To  carry  sensations  to  the  mind. 
cial  Senses.       \  2.  To  produce  ideas  in  the  mind. 


The    Sense 
Taste. 


The    Sense 
Smell. 


The    Sense 
Hearing. 


The    Sense 
Seeing. 


of 


of 


of 


of 


The  Organs  of 
Speech. 


r  I.  Taste  a  sentinel  guarding  the  stomach. 
J   2.  The  gustatory  nerve, 
j   3.  How  flavors  are  perceived, 
[^  4.  Palatable  foods. 

f  r.  The  olfactory  nerve. 
J   2.  How  odors  are  perceived. 
I   3.  Agreeable  and  disagreeable  odors. 
[_  4.  A  guard  to  eating  and  brea/thing. 

r  I.  Sound-vibrations  :  the  auditory  nerve — ^hearing. 

J   2.  The  ear:  external  —  middle — internal  —  Eusta- 
~j  chian  tube. 

(_  3.  Care  of  the  ear. 

r.  Light-vibrations  :  the  optic  nerve — sight. 

2.  Need  of  light : 

1.  To  protect  the  body  from  injury. 

2.  l"o  observe  beauty  in  the  world. 

3.  The  eye  :  form  and  position — structure — muscles. 

4.  Action  of  light :  how  regulated — produces  vision 

5.  Care  of  the  eye  :  direction  of  light — use  of  glasses 

— intensity  of  light. 

1.  The  need  of  expression. 

2.  The  voice  :    the    larynx — the  glottis — ihe  vocal 

cords. 

3.  Speech  :  pitch — quality — quantity — articulation. 

4.  Care  of  the  voice — pleasant  tones — avoid  strain- 

ing the  voice. 

Hygiem  of  the  organs  of  special  sense. 
Something  to  find  out. 


i66 


BONES  OF   THE  BODY. 


BONES  OF  THE  BODY. 


The  Head — 29  Bones. 


Skull. 
(8  bones.) 


Front' al  {frontale,  frontlet — one  in  forehead). 

Pa-ri'e-tal  {paries,  wall — one  on  each  side  of  head). 

Tem'po-ral  {tempus,  time — one  in  each  temple). 

Sphe'noid  {sphenos,  wedge — one  at  base  of  skull,  be- 
tween temples  and  cheeks). 

Eth'moid  {ethmos,  sieve — one  between  cavity  of  skull 
and  upper  part  of  nose). 

Oc-cip'i-tal  {occiputy  back  of  head — one  at  base  of 
skull). 


Ears. 
(6  bones.) 


{Mal'le-uj 
In'cus  (a 
Sta'pes  (; 


-us  (mallet — outermost  of  chain,  one  in  each  ear), 
(anvil — middle  of  chain,  one  in  each  ear), 
stirrup — innermost  of  chain,  one  in  each  ear). 


Face. 
(14  bones. )f 


Lach'ry-mal  {lacryma,  tear — one  in  each  orbit). 

Na'sal  (nast4s,  nose — two,  forming  bridge  of  nose). 

Ma'lar  {malay  cheek — one  in  each  cheek). 

Tur'bi-nate  {turben,  whirl — ^^one  in  outer  wall  of  each 
nostril). 

Pal'a-tal  {palatum,  palate — two,  completing  skeleton 
of  hard  palate). 

Vo'mer  (plowshare — separating  nostrils). 

Su-pe'ri-or  Max'il-la-ry  {superior  maxilla,  upper  jaw- 
bone— two,  forming  upper  jaw). 

In-fe'ri-or  Max'il-la-ry  {inferior,  lower — one  in  lower 
jaw). 

Hy'oid  (y  and  eidos,  form,  w-shaped — one  in  neck  at 
base  of  tongue). 


*  In  early  life  there  is  a  fourth  bone  between  the  incus  and  the 
stapes  in  each  ear,  but  later  it  becomes  a  part  of  the  incus. 

f  As  the  teeth  are  developed  from  the  mucous  membrane,  they  are 
not  usually  looked  upon  as  belonging  to  the  skeleton.  The  temporary, 
or  "  milk,"  set  contains  eight  incisors,  four  canines,  and  eight  molars. 
The  permanent  set  may  be  tabulated  as  follows : 

In-ci'sors  {incido,  to  cut — four  in  the  front  of  each  jaw). 
Ca-nines'  {canis,  dog — one  on  each  side  of  each  jaw,  behind  the 

incisors). 
Bi-cus'pids  {bi,  two,  and  cuspis,  prominence — two  on  each  side 

of  each  jaw  behind  the  canines). 
Mo'lars  {mola,  mill — three  on  each  side  of  each  jaw,  behind  the 
bicuspids). 


■^  a 

I! 


BONES  OF  THE  BODY. 


167 


The  Trunk*— 57  Bones. 


Spine. 
(24  bones.) 


Shoulder. 
(4  bones.) 


Cer'vi-cal   Ver'te-brae   (cervix^   neck  —  seven   in   the 

neck). 
Dor'sal    Ver'te-brse   {dorsuniy   back  —  twelve    in    the 

back). 
Lum'bar  Ver'te-brse  {lumbus^  loin — five  in  the  loins). 

f  Scap'u-la  (shoulder-blade — one  on  upper  part  of  back 
j       on  each  side). 

j  Clav'i-cle  {clavis,  key — one  on  each  side,  between  top 
[      of  breastbone  and  point  of  shoulder). 


Sternum  {sternoHy  breast 
chest). 


one  extending  vertically  along  middle  of 


Ribs. 
(24  bones.) 


Pelvis. 
(4  bones.) 


True  (upper  seven  pairs  attached  to  spine,  and  tied 
directly  to  breastbone  by  cartilages). 

False  (lower  five  pairs  attached  to  spine  ;  three  pairs 
tied  to  cartilages  of  preceding  rib  ;  two  pairs  "  float- 
ing" unattached  in  front). 

In-nom'-i-nate  (?«,  not,  and  nomino,  to  name — two 

main  bones  of  pelvis,  forming  hips). 
Sa'crum    (sacred — one    between    innominate    bones, 

formed  of  five  consolidated  vertebrae). 
Coc'cyx  (cuckoo — one  below  sacrum,  formed  of  four 

consolidated  vertebrae). 


The  Limbs— 120  Bones. 


Upper. 
(6obones.)t 


Hu'me-rus  (upper  arm — one  in  each  arm). 

Ul'na  (elbow — one   in  each  forearm,  joined   to  the 

humerus). 
Ra'di-us  (spoke — one   in   exterior  of  each   forearm, 

moving  around  ulna). 
Car'pal  {carpus,  wrist — eight  in  each  wrist). 
Met-a-car'pal   {meta,   beyond,   carpus,  wrist — five   in 

each  hand,  between  wrist  and  fingers). 
Pha-lan'ges  (battalions — three  in  each  finger,  two  in 

each  thumb). 


*  Strictly,  the  scapula  and  the  clavicle  belong  neither  to  the  trunk 
nor  the  arms,  but  simply  connect  them.  The  sacrum  and  the  coccyx 
may  be  classified  as  belonging  to  the  spine. 

f  At  the  joints  of  the  thumbs  and  great  toes  are  pairs  of  small  bones, 
eight  in  all,  called  sesamoid  bones  isesamon,  sesame-seed,  and  eidos,  like^ 


1 68 


BONES  OF   THE  BODY. 


Lower. 
(60  bones.) 


Fe'mur  (thigh-bone — one  in  each  leg). 

Pa-tel'la  (little  pan — one  covering  each  knee-joint). 

Tib'i-a  (shin-bone — one  in  each  leg,  between  knee 

and  ankle). 
Fib'u-la  (clasp — one  bracing  tibia  in  each  leg). 
Tar'sal  {tarsus,  flat  of  foot — seven  in  eaj:h  instep). 
Met-a-tar'sal  {meta,  beyond,  and  tarsus — five  in  each 

foot,  between  ankle  and  toes). 
Pha-lan'ges  (battalions — two  in  each  great-toe,  three 

in  each  of  the  others).* 


*  The  confusion  about  the  number  of  bones  in  the  body  arises  from 
counting  them  at  different  ages  and  omitting  different  sets.  The  fol- 
lowing successive  additions  will  explain  the  various  numbers  : 

General  bones  of  the  skeleton 200 

Bones  of  the  ear  in  adults 6 

206 
Additional  bones  in  the  ear  in  children 2 

208 
The  pennanent  teeth 32 

240 
The  sesamoid  bones 8 


248 


WHERE  TO  FIND  THINGS. 


Abdomen,  35. 
Absorbent  vessels,  37. 
Absorption,  41. 

by  blood-vessels,  96. 

by  the  lacteals,  41. 

by  the  skin,  91,  96. 

of  the  food,  37. 
Acid,  muriatic,  79,  89. 
Adam's  apple,  50. 
Air,  atmospheric,  124. 

changes  in,  in  respiration,  52. 

carbonic  acid  in,  52. 

dust  in  the,  52. 

effects  of  impure,  54,  118. 

impurities  in,  54. 

need  of  ventilation,  55,  57.* 

pressure  of,  51. 

provision  for  purifying,  46. 

waste  matter  expired  in,  52. 
Air-cells  of  the  lungs,  50. 
Air-passages,  50. 
Albinos,  94,  129. 
Albumen,  22. 
Albuminoid  substances,  23. 

varieties  of,  23. 
Alcohol,  6,  140. 

effects  upon  the  brain,  116. 

effects  upon  digestion,  37. 

effects  upon  the  face,  62. 

effects  upon  the  heart,  62,  117. 

effects  upon  the  mind,  117. 

effects  upon  the  nerves,  113, 116, 
118. 


Alcohol,  habit  of  drinking,  38, 138k 

hostile  to  life,  37,  41,  117. 

in  the  arteries,  62. 

in  the  blood,  53,  61. 

in  the  breath,  53,  118. 

in  the  liver,  41. 

in  the  lungs,  53. 

in  the  stomach,  37. 

the  poisonous  effects  of,  38. 

unchanged  in  the  stomach,  38. 
Alimentary  canal,  68,  137. 
Alkali,  40,  43,  138. 
Amyloids,  23. 
Animal  functions,  4. 
Animal  heat,  23,  37. 

how  produced,  23. 

regulated  by  perspiration,  95. 
Antagonistic  muscles,  69,  87. 
Antoinette,  Marie,  100. 
Anxiety  affects  the  hair,  100. 
Aorta,  59. 
Appetite,  43. 

inherited,  118. 
Apples,  25. 

Application  of  knowledge,  7. 
Aqueous  humor,  130. 
Arch  of  the  foot,  84,  87. 
Arms,  15,  83. 
Aroma,  124. 
Arrowroot,  23. 
Arterial  blood,  53. 

differs  from  venous,  52,  53. 
Arteries,  48,  58. 


I/O 


WHERE   TO  FIND    THINGS. 


Arteries,  distribution  of,  59. 

pulsation  of,  60. 

structure  of,  59. 
Athletic  sports,  74. 
Auditory  canal,  126. 

nerves,  125. 
Auricles  of  the  heart,  48, 

Backbone,  82. 
Ball-catcher,  87. 
Bathing,  97. 

importance  of,  97. 

time  and  manner  of,  98. 
Baths,  97,  98. 

different  kinds  of,  98. 

of  soup,  96. 

of  wine,  96. 
Bath-tub,  98. 
Beans,  23,  24. 
Beauty  in  the  world,  128. 
Beef,  24. 
Beer,  75. 
Beets,  23. 
Beverages,  139. 
Biceps  muscle,  86. 
Bile,  39. 

secretion  of,  in  the  liver,  40. 

uses  of,  40,  43. 
Blackberries,  25. 
Blacksmith,  70. 

Bleeding,  how  stopped,  64,  65. 
Blonde  complexion,  92. 
Blood,  58. 

arterial,  53. 

change  of  color,  53,  61. 

circulation  of,  58. 

clotting  of,  64. 

course  of,  60,  61. 

injured  by  chewing  tobacco,  31. 

making  of,  18. 

purification  of,  in  lungs,  46,  52. 

uses  of  the,  18. 

venous,  46. 
Blood-vessels,  48,  129. 

of  the  skin,  96, 

absorption  by,  96. 

injuries  to,  60,  61,  63. 
Blushing,  96. 
Bodily  covering,  91. 


Bodily  motion  directed,  107. 
Body,  13. 

care  of,  18. 

cavities  of,  85. 

clothing  of,  73,  100,  loi. 

movements  of,  73,  85. 

of  other  animals,  17. 

repair  of,  58. 

temperature  of,  95. 

uses  of  parts  of,  18. 

why  we  should  study  the,  13. 
Bones,  77. 

color  of,  79. 

composition  of,  79. 

deformity  of,  85,  88,  89,  103. 

growth  of,  80. 

hygiene  of,  88. 

moved  by  muscles,  85. 

of  arms,  83. 

of  head,  80. 

of  legs,  84. 

of  trunk,  81. 

repair  of,  80. 

size  and  shape  of,  78. 

structure  of,  78. 

uses  of,  77. 
Brain,  108. 

care  of,  118,  119. 

congestion  of,  116. 

effects  of  alcohol  upon,  116. 

exercise  of,  115,  118. 

function  of,  114. 

injuries  of,  116. 

sensitiveness  of,  85. 

softening  of,  116. 

structure  of,  109. 
Bread,  22. 

and  butter,  25. 
Breast-bone,  83. 
Breath,  effect  of  alcohol  upon,  31. 

53,  57- 

effect  of  tobacco  upon,  31. 
Breathing,  51,  52,  124. 

control  of,  113. 

forces  in,  51. 

process  of,  51. 
Bronchi,  50. 
Bronchial  tubes,  50. 
Brunette  complexion,  92.  - 


WHERE   TO  FIND    THINGS, 


171 


Bunions,  85. 
Burns,  106. 
Butter,  25. 

Calisthenics,  74. 

Callus,  92. 

Candy,  43. 

Capillary  blood-vessels,  59. 

circulation  in  the,  60. 
Carbonic  acid,  52. 

exhaled  from  the  lungs,  52. 

in  the  air,  52. 

supports  vegetable  life,  52. 
Cardia,  36. 
Cartilage,  82,  83. 
Caseine,  23. 
Catarrh,  103. 
Cavities  of  body,  35. 
Cells,  nerve,  108. 
Cerebellum,  109. 

function  of  the,  117. 
Cerebrum,  109. 

function  of  the,  117. 
Cheek-bone,  86. 
Cheeks,  26. 
Cheese,  23. 
Cherries,  25. 
Chest,  35. 

frame-work  of,  82*. 

variation  in  size  of,  50. 
Chewing  of  food,  26. 
Chicken,  24. 
Chilliness,  loi,  104. 
Choroid  coat  of  the  eye,  129. 
Chyle,  41. 
Chyme,  37. 

Cigarette-smoking,  54. 
Circulation,  58. 

cause  of,  58. 

hygiene  of,  62. 

of  the  blood,  58. 

rapidity  of,  60. 

through  the  heart,  59. 

through  the  lungs,  52. 
Circus,  76. 
Clams,  24. 
Cleanliness,  97. 

helps  morality,  97. 

of  animals,  97. 


Clavicle,  83. 
Clot,  64. 
Clothing,  100,  104. 

not  to  be  worn  tight,  55,  88,  103. 

poisonous,  103. 

should  hang  from  shoulders,  55. 
Coffee,  22. 

Colds,  95,  loi,  103,  126. 
Collar-bone,  83. 
Color,  differences  in,  128. 
Coloring-matter,  92,  129. 
Column,  spinal,  82. 
Comfort,  97. 
Complexion,  92. 

affected  by  heat  and  light,  93. 
Connective  tissue,  67. 
Consumption,  53,  103. 
Contraction  of  heart,  46,  59. 

of  muscles,  68. 
Convolutions  of  the  brain,  109. 
Cooking,  24. 
Cords,  vocal,  132. 
Cornea,  129. 
Corn-meal,  24. 
Corns  on  the  feet,  85,  92. 
Cotton,  loi. 
Coughing,  113. 
Covering,  bodily,  91. 
Crabs,  24. 

Cramming  for  examination,  119. 
Cross-eyes,  130. 
Crystalline  lens,  130. 

uses  of,  131. 
Currants,  25. 
Curvature  of  spine,  89. 
Cuticle,  92. 

structure  of,  92. 
Cutis  vera,  93. 

Dandruff,  92. 

Danger  from  eating,  43,  124. 

Death,  66. 

caused  by  alcohol,  37,  117. 
Deformity,  102. 

of  bones,  88. 

of  feet,  85,  103. 

of  legs,  88. 

of  shoulders,  74,  75. 

of  waist,  88,  103. 


1/2 


WHERE   TO  FIND   THINGS. 


Delirium,  117. 

Dentine,  27. 

Derma,  93. 

"Deserted  Village,"  135. 

Diaphragm,  movements  of  the,  in 

respiration,  35,  51. 
Diet,  mixed,  25. 

necessity  of  a  regulated,  43. 
Digestion,  35. 

circumstances  affecting,  43,  99. 

effects  of  alcohol  upon,  37,  44. 

effects  of  tobacco  upon,  44. 

general  plan  of,  42. 

hygiene  of,  43. 

in  the  intestines,  38. 

in  the  stomach,  36. 

nature  of,  35. 

organs  of,  35,  38,  39,  40. 
Digitigrade,  19. 
Direct  nerve-action,  112. 
Dirt,  97. 
Drainage,  55. 
Drink,  37. 
Drunken  oess,  117. 
Duct,  thoracic,  42. 
Duodenum,  39. 

Ear,  125. 

bones  of  the,  127. 

care  of,  127. 

drum  of  the,  126. 

external,  125, 

foreign  bodies  in  the,  127. 

internal,  126. 

middle,  126. 

wax  of,  127. 
Earache,  14. 
Ear-wax,  127. 
Eating,  21. 
Eat,  what  we,  21. 
Eggs,  23,  24. 
Elbow,  bending  of,  86. 
Emergencies,  64,  65. 
Emotion,  100. 

affects  the  nerves,  116. 
Enamel  of  the  teeth,  27. 
Envy,  116. 
Epidermis,  92. 
Epiglottis,  31. 


Epiglottis,  uses  of,  31. 
Esophagus,  31. 
Eustachian  tube,  126. 
Exercise,  71,  72. 

different  modes  of,  74,  75. 

effects  of,  61. 

excessive,  72. 

for  health,  not  strength,  71. 

importance  of,  63,  88,  103,  iiS. 

of  the  nerves,  115. 

open-air,  65. 
Expiration,  52. 

movements  of,  52. 
Extensor  muscles,  69. 
Eye,  128. 

care  of,  103,  131,  133. 

muscles  of,  87. 

of  a  cat,  130,  135. 

of  an  ox,  131. 

structure  of,  129. 
Eyeball,  128. 
Eyelashes,  128. 
Eyelids,  99,  128. 

Fainting,  116. 
False  ribs,  83. 
Farming,  22. 
Fats,  23. 

source  of,  in  food,  23. 
Fear  affects  the  hair,  lOO. 
Femur,  84. 
Fibers,  muscular,  67,  68. 

nerve,  108. 
Fibrils,  67. 
Fibrine,  23. 
Fibula,  84. 
Fire-kings,  96. 
Fish,  as  food,  24. 
Flannels,  loi. 
Flavors,  122,  123. 
Flesh,  24. 
Flexor  muscles,  69. 
Floating  ribs,  83. 
Flour,  22. 
Flowers,  134,  135. 
Foods,  22,  23,  24,  25,  123. 

animal,  24. 

changes  of,  42. 

elements  of,  22. 


WHERE   TO  FIND   THINGS. 


173 


Foods,  kinds  of,  22. 

mixture  of,  25. 

necessity  for,  18. 

source  of,  22. 

special,  24. 

vegetable,  24. 
Foot,  15. 

arch  of,  84,  87. 

care  of,  84,  88. 
Freckles,  93 
Fruits,  25. 

benefits  of,  25. 

ripe,  25. 

unripe,  25. 
Full  bath,  99. 
Function,  4. 
Furs,  loi. 

Ganglions,  iii. 
Gas,  sewer,  55. 
Gastric  juice,  36. 

action  of,  36. 

effect  of  alcohol  upon,  37. 
Gelatine,  23. 
Geography,  22. 
Glands,  perspiratory,  94. 

salivary,  29. 

sebaceous,  94. 

tear,  128. 
Glasses,  131. 

concave,  131. 

convex,  131. 
Glottis,  132. 
Gluten,  22. 
Goldsmith's   "Deserted  Village," 

135- 
Graham  flour,  24. 
Grief,  116,  128. 
Gristle,  80. 

Growth  of  brain  and  mind,  115,  Ii8. 
Gum,  chewing,  30. 
Gums,  vegetable,  23. 
Gustatory  nerves,  123. 
Gymnastics,  74. 

Habit,  114,  118,  120. 
Hand,  the,  15. 
Hair,  91,  92,  99. 
care  of,  99,  104. 


Hair,  grayness  of,  100. 

shedding  of,  99. 

structure  of,  99. 

sudden  change  of  color,  100. 

thinning  of,  100. 

uses  of,  99. 
Hair-follicles,  94. 
Harmony  of  bodily  organs,  107. 
Headache,  14. 
Health,  importance  of,  15. 
Hearing,  sense  of,  125. 

may  be  cultivated,  125. 

protection  of,  127. 
Heart,  46. 

affected  by  alcohol,  117. 

affected  by  tobacco,  118. 

cavities  of,  48. 

circulation  through  the,  59. 

frequency  of  action,  60. 

movements  of,  48. 

structure  of,  48. 

valves  of,  48. 

work  of,  46,  60. 
Heat,  animal,  23,  37. 

foods  productive  of,  23. 

regulation  of,  loi. 
Hiccough,  113. 
High  heels,  85,  103. 
Hollow  muscles,  68. 
Homes,  135. 
Humems,  83. 
Humor,  aqueous,  130. 

crystalline  lens,  130. 

vitreous,  130. 
Hunger,  43, 
Hygiene,  5. 

of  the  bones,  88. 

of  the  circulation,  62. 

of  digestion,  43. 

of  mastication,  32. 

of  the  muscles,  72. 

of  the  nerves,  118. 

of  the  organs  of  special  sense^  133. 

of  respiration,  55. 

of  the  skin,  103. 

Ideas,  122. 
Ill-temper,  116. 
Impurities  on  the  skin,  97. 


1.74 


WHERE   TO  FIND    THINGS. 


Incentives  to  study,  5. 
Inferior  vena  cava,  48. 
Inheritance,  118. 
Ingrowing-nails,  85. 
Insanity,  drunkenness  a  form  of, 

121. 
Insensibility  caused  by  tobacco,ii8. 
Insensible  perspiration,  95. 
Inspiration,  52. 
Intercostal  muscles,  51. 
Intestinal  juices,  38. 

action  of,  38. 
Intestinal  digestion,  38. 
Intestines,  38. 

motion  of,  38. 

structure  of,  38. 
Involuntary  muscles,  6g. 
Iris,  68,  130. 

function  of,  131. 
Iron,  23. 

Jaundice,  40. 
Jaw,  lower,  81,  86. 
Joints,  15. 

ball-and-socket,  16. 

compound,  16. 

hinge,  16. 

motion  in,  16. 

pivot,  83. 
Juice,  gastric,  36,  43. 

intestinal,  38,  42. 

pancreatic,  39,  40,  43. 
Jumping,  87. 

Kidneys,  95. 

Kissing,  sometimes  dangerous,  96. 

Knee,  16. 

Lacteals,  41. 

absorption  by,  41. 
Lamb,  24. 

Large  intestines,  38. 
Larynx,  50. 

production  of  the  voice  in  the, 
132. 
Layers  of  the  skin,  92. 
Leaping,  87. 
Legs,  15,  84,  88. 
Legislative  action,  3. 


Lens,  crystalline,  130. 
Ligaments,  68. 
Light,  theory  of,  127. 

action  on  eye,  128,  131. 

need  of,  128. 
Limbs,  15. 

Lime  in  the  bones,  88. 
Linen,  loi. 
Liver,  40. 

alcohol  in,  41. 

secretion  of  the,  40. 
Lobes  of  lungs,  49,  50. 
Lobsters,  24. 
Long-sight,  131. 
Looks,  importance  of,  14. 
Lungs,  49. 

action  in,  52. 

structure  of,  50. 
Lymph,  96. 

vessels,  96. 

Macaroni,  33. 
Manufacturing,  22. 
Marie  Antoinette,  100. 
Marrow  of  the  bones,  78. 
Masseter,  86. 
Mastication,  25. 

hygienic  laws  of,  32. 

importance  of,  30. 
Meanness,  116. 
Meats,  23. 

the  cooking  of,  24. 
Medulla  oblongata,  iii. 

function  of  the,  113. 
Melons,  25. 

Membrane  of  the  tympanum,  126. 
Microscope,  108. 
Milk,  24. 

mixed  with  lime-water,  25. 
Mind,  effects  of  alcohol  upon,  117. 

growth  of,  115,  119. 
Minerals,  23. 
More,  Sir  Thomas,  ico. 
Morning-bath,  98. 
Motion  necessary  to  life,  66. 
Mucous  coat,  36. 

membrane,  145. 
Muriatic  acid,  79,  89. 
Muscles,  67. 


WHERE   TO  FIND    THINGS. 


175 


Muscles,  antagonistic,  69,  87. 

extensors,  69. 

flexors,  69. 

function  of,  67,  85. 

hollow,  68. 

hygiene  of,  72. 

in  pairs,  69. 

need  rest,  71,  73. 

of  the  eye,  87,  130. 

structure  of,  67. 

voluntary  and  involuntary,  69. 
Muscular  contraction,  68. 
Muscular  coat,  36,  38. 

fibers,  67. 

sense,  122. 
Miisic,  122,  125,  135. 

Nails,  92. 

ingrowing,  85. 

uses  of  the,  92,  105. 
Narcotics,  30,  75,  139,  140. 

property  of,  30. 

tobacco,  30,  140. 
Nasal  cavities,  51. 
Nerve-action,  112. 

direct,  112. 

reflex,  112. 
Nerve-matter,  108. 

cells,  108. 

fibers,  108. 
Nerves,  107. 

aff"ected  by  alcohol,  116. 

affected  by  emotion,  116. 

affected  by  tobacco,  1 17. 

auditory,  125. 

exercise  of,  115. 

functions  of,  ill. 

gustatory,  123. 

how  distributed,  107,  iii. 

hygiene  of,  118. 

motor,  112. 

olfactory,  124. 

optic,  128. 

sensory,  112. 

spinal,  III. 

structure  of,  108. 

sympathetic  system  of,  iii,  114. 
Nervous  system,  107. 
Nose,  17,  52,  124. 


Nurture,  21,  58. 
Nutrition,  60. 

Odors,  122,  124,  135. 

Oil  as  food,  23. 

Oil-glands,  94,  96. 

Old-sight,  131. 

Olfactory  nerve,  124. 

Opium,  140. 

Opium-eaters,  140. 

Optic  nerve,  128. 

Oranges,  25. 

Organs  of  circulation,  46,  59, 

of  digestion,  35,  38,  39. 

of  hearing,  125. 

of  respiration,  49. 

of  sight,  128. 

of  smell,  124. 

of  taste,  123. 

of  touch,  122. 

of  voice,  132. 
Orris-root,  29. 
Overshoes,  102. 
Oxygen,  46,  52. 

given  off  by  plants,  52. 

received  into  the  blood,  52. 
Oysters  as  food,  24,  33. 

Pairs  of  parts  of  the  body,  17. 
Palate,  132. 
Paleness,  96. 
Pancreas,  39. 
Pancreatic  juice,  39,  43. 

uses  of,  40. 
Papillae,  94. 
Paralysis,  116. 
Passages,  air,  50. 
Passions,  117. 
Patella,  84. 
Peaches,  25. 
Peas,  23,  24. 
Pelvis,  82. 
Peifumery,  133. 
Pericardium,  47. 
Periosteum,  79. 
Perspiration,  94. 

daily  amount  of,  95. 

sensible  and  insensible,  95. 

uses  of,  95. 


176 


WHERE   TO  FIND    THINGS. 


Pharynx,  31. 
Physical  strength,  71. 

culture,  73,  74. 
Piano-playing,  115. 
Pigment,  92,  99. 
Pitch  of  sound,  132. 
Plantigrade,  19. 
Plays,  74,  75,  121. 
Pleura,  51. 
Pneumonia,  53,  103. 
Pork,  24. 
Portal  vein,  41. 
Posture,  73. 
Potash,  23. 
Potato,  23. 

Preservation  of  the  teeth,  28,  32. 
Prism,  128. 
Proteids,  23. 
Pulmonary  action,  48. 
Pulmonary  heart,  48. 
Pulmonary  vein,  53. 
Pulsation  of  the  heart,  60. 

of  the  arteries,  60. 
Pulse,  60. 
Pupil,  the,  130. 
Pylorus,  36. 

Radius,  84, 
Raspberries,  25, 
Redness  caused  by  drink,  116. 
Reflex  action  of  the  spinal  cord, 
112. 

objects  of,  113. 

uses  of,  113. 
Repair,  58. 

of  muscles,  70,  71. 
Respiration,  52. 

change  of  blood  in,  52. 

hygiene  of,  55. 

movements  of,  51. 

object  of,  46, 

organs  of,  49. 
Rest,  necessity  for,  116,  119. 
Retina,  129. 

image  on,  131. 
Ribs,  82. 

movements    of,    in    respiration, 

51. 
Rice,  22. 


Roof  of  mouth,  132. 
Round  shoulders,  75. 

Sago,  23. 
Saliva,  29. 

amount  needed,  30. 

flow  of,  29. 

secretion  of,  29, 

use  of,  29,  36. 

waste  of,  30. 
Salivary  glands,  29. 
Salt,  common,  22,  23. 
Saltness,  123. 
Sartorius  muscle,  87. 
Scalp,  92,  100,  104. 
Scapula,  83. 
Scarf-skin,  92. 

Sclerotic  coat  of  the  eyeball,  129. 
Screaming,  133. 
Sebaceous  glands,  94. 

secretion  of,  94. 
Selfishness,  116, 
Sensation,  122. 

of  temperature,  122. 

of  weight,  122. 

production  of,  122. 
Sense  of  hearing,  125. 

of  sight,  127. 

of  smell,  124, 

of  taste,  122. 

of  touch,  122. 
Sense,  muscular,  122. 
Senses,  special,  122. 
Sensory  nerves,  112,  119. 
Serous  coat,  36. 
Serum,  36. 

Shocks,  how  distributed,  84,  87. 
Shoes,  84,  loi,  103. 
Short-sight,  131. 
Shoulder-blade,  83. 
Shoulders,  round,  75. 
Sight,  sense  of,  127. 

organs  of,  128. 
Silk,  loi. 

Sir  Thomas  More,  100. 
Sitting,  73. 

Skeleton,  80,  81,  82,  83,  84,  85. 
Skill,  1 15. 
Skin,  92, 


WHERE   TO  FIND    THINGS. 


177 


Skin,  absorption  by,  91,  96. 

care  of,  97. 

casts  out  waste  matter,  91,  94. 

how  kept  soft,  94. 

hygiene  of,  103. 

layers  of,  92. 

regulates  heat,  91,  95. 

rubbing  of,  98,  103. 

should  be  kept  clean,  96,  97. 

structure  of,  92. 
Skull,  80. 

sutures  of  the,  81. 

uses  of  the,  80,  85. 
Slaughter-house,  135. 
Sleep,  necessity  for,  116,  119. 
Small  intestines,  38. 
Smell,  sense  of,  124. 

nerve  of,  124. 

uses  of,  124. 
Smoking,  effects  of,  54. 

cigarette,  54. 
Sneezing,  113. 
Soap,  98,  99. 
Soda,  23,  44. 

Softening  of  the  brain,  116. 
Soles  of  the  feet,  92,  94. 
Something  to  find  out,  19,  32,  44, 

56,  63,  75,  89,  105,  120,  134. 
Sound,  production  of,  125,  132. 

pitch  of,  125. 
Soups,  24. 

preparation  of,  24. 
Sourness,  123. 

Spasms  caused  by  tobacco,  118. 
Special  senses,  122. 
Speech,  125,  132. 

organs  of,  132. 

production  of,  132. 
Spinal  column,  82. 
Spinal  cord,  82,  ill. 

functions  of  the,  113. 

nerves  of,  iii. 

reflex  action  of,  II2. 
Spine,  curvature  of,  89. 
Spleen,  39,  153 
Sponge-bath,  98. 
Starch,  23. 

its  change  into  sugar,  36,  42. 
Sternum,  83. 


I  Stimulants,  75.  i37,  138. 
Stomach,  35. 

absorption  in,  37,  41. 

alcohol  in,  37. 

digestion  in,  36. 

movements  of,  36, 

secretion  ^)f,  36. 

structure  of,  36. 
Strawberries,  25. 
Strength,  71. 
Striated  muscles,  67. 
Study,  no,  112,  118. 
Subclavian  vein,  42. 
Sugar,  22. 
Sulkiness,  116. 
Superior  vena  cava,  48. 
Sutures,  81. 
Swallowing,  29. 

Sweat-glands,  number  of,  94,  95. 
Sweet-bread,  in  animals,  40. 
Sweetmeats,  43. 
Sweetness,  123. 
Swell  of  muscles,  68. 
Swine,  124. 
Sympathetic  system  of  nerves,  in 

114. 
Systemic  heart,  48. 

Tainted  food,  124. 
Tan,  93. 
Tannery,  135. 
Tapioca,  23. 
Tartar,  29. 
Taste,  122,  123. 

as  a  sentinel,  122. 

injury  of,  133. 

organ  of,  123. 

sense  of,  122. 
Tea,  22. 

Tear -gland,  128. 
Tears,  128. 

escape  of  the,  128. 

secretion  of,  128. 
Teeth,  26,  132. 

arrangement  of,  26. 

bicuspids,  26. 

canine,  or  cuspids,  26. 

incisors,  26. 

molars,  26. 


178 


WHERE   TO  FIND    THINGS. 


Teeth,  of  different  animals,  26. 

permanent,  34. 

preservation  of,  28,  32. 

structure  of,  27. 
Temperature  of  the  body,  95. 

extremes  of,  96,  loi. 

sensations  of,  122. 
Tendons,  68. 
Thinking,  118. 
Thirst,  96. 
Thoracic  duct,  42. 
Thorax,  83. 
Thought,  118. 
Throat-deafness,  126. 
Tibia,  84. 

Tight  clothing,  103. 
Tight  shoes,  84. 
Tissue,  connective,  67. 
Tobacco,  30. 

effects  upon  the  body,  54,  140. 

effects  upon  the  breath,  31,  55. 

effects  upon  the  heart,  117,  140. 

effects  upon  the  lungs,  54, 57, 140. 

effects  upon  the  mind,  54. 

effects    upon    the   nerves,    117, 
118,  140. 

effects  upon  the  stomach,  31. 

filthiness  of,  31,  55,  140. 

saliva  wasted  by  chewing,  30. 
Tongue,  26,  132. 

nei-ves  of,  123. 
Tooth-brush,  28. 
Tooth-pick,  28. 
Touch,  delicacy  of,  122. 

organs  of,  122. 

sense  of,  122,  123. 
Trachea,  50. 
Training,  115, 
Triceps  muscle,  86. 
True  skin,  93. 
Trunk,  35. 

bones  of,  81. 

cavities  of,  35. 
Turkey,  24. 
Turnips,  23. 
Tympanum  of  the  ear,  126. 

membrane  of,  126. 


Ulna,  84. 

Unconscious  movements,  113. 

Valves  of  the  heart,  48. 

of  the  veins,  61. 
Varicose  veins,  61. 
Veal,  24, 
Vegetable  food,  24. 

respiration,  52. 
Veins,  41,  42,  48,  59. 

circulation  in,  61. 

distribution  of,  59. 

structure  of,  59. 

valves  of,  61. 

varicose,  61. 
Venous  blood,  46. 

changes  of,  in  respiration,  52. 
Ventilation,  54,  57. 
Ventricles  of  the  heart,  48. 
Vertebrae,  82. 
Vibration,  125,  126. 
Vitreous  humor,  130. 
Vocal  cords,  132. 

action  of,  132. 
Voice,  132, 

care  of,  133,  134. 

organs  of,  132. 

production  of,  132. 

varieties  of,  133,  136. 
Voluntary  muscles,  69. 

Walking,  85. 

as  a  means  of  exercise,  76. 
Waste,  58,  91,  94,  95. 
Water,  23,  95. 
Water-proofs,  102. 
Weeping,  128. 
Wheat,  22. 
Wheat-flour,  22. 
Whisky,  37,  57,  118. 
Will,  impairment  of,  117. 
Windpipe,  50, 
Wine,  37. 
Winking,  128. 
Woolens,  loi. 
Words,  132. 
.Worry  affects  the  hair,  100, 


; 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
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